updating repo

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diff --git a/Engineering_Physics/Chapter1.ipynb b/Engineering_Physics/Chapter1.ipynb
deleted file mode 100755
index a3614569..00000000
--- a/Engineering_Physics/Chapter1.ipynb
+++ /dev/null
@@ -1,357 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter1",
-  "signature": "sha256:e55f587b2da98ead68f73bb2b4d29bef91aa67eb577c460fb9dcaab92acc4339"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "1: Ultrasonics"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.1, Page number 20"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.33;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",d1, \"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 237.6 m\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.2, Page number 21"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 40;     #length of iron rod(mm)\nE = 115*10**9;      #Young's modulus(N/m**2)\nrho = 7.25*10**3;   #density of pure iron(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;             #natural frequency of the rod(kHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"depth of the submerged submarine is\",new, \"kHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 49.785 kHz\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.3, Page number 21"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 1;     #length of quartz crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;                   \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"fundamental frequency of crystal is\",new, \"*10**6 Hz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "fundamental frequency of crystal is 2.73 *10**6 Hz\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.4, Page number 22"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 0.55;        #distance between 2 constructive antinodes(mm)\nnew = 1.5;      #frequency of crystal(MHz)\n \n#Calculation\nnew = new*10**6;        #frequency of crystal(Hz)\nd = d*10**-3;     #distance between 2 constructive antinodes(m)\n#distance between 2 antinodes is given by lamda/2\nlamda = 2*d;      #wavelength of ultrasonic waves(m)\nv = new*lamda;       #velocity of waves(m/s)\n\n#Result\nprint \"velocity of waves is\",int(v), \"m/s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "velocity of waves is 1650 m/s\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.5, Page number 22"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 50;     #length of rod(mm)\nE = 11.5*10**10;      #Young's modulus(N/m**2)\nrho = 7250;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;       #natural frequency of the rod(kHz)\nnew = math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"natural frequency of rod is\",new, \"kHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "natural frequency of rod is 39.83 kHz\n"
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.6, Page number 22"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 2;     #length of crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;         #natural frequency of the rod(MHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"MHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "frequency of crystal is 1.365 MHz\n"
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.7, Page number 23"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 3;     #length of crystal(mm)\nE = 8*10**10;      #Young's modulus(N/m**2)\nrho = 2500;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;         #natural frequency of the rod(kHz) \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"kHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "frequency of crystal is 942.81 kHz\n"
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.8, Page number 23"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 1.5;     #length of crystal(mm)\nE = 7.9*10**10;      #Young's modulus(N/m**2)\nrho = 2650;   #density(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-6;         #natural frequency of the rod(MHz) \nnew=math.ceil(new*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"frequency of crystal is\",new, \"MHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "frequency of crystal is 1.82 MHz\n"
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.9, Page number 24"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.95;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of sea(m)\n\n#Result\nprint \"depth of the submerged submarine is\",int(d1), \"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 684 m\n"
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.10, Page number 24"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.83;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",d1, \"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 597.6 m\n"
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.11, Page number 24"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\naS = 1050;      #total absorption inside hall(Sabine)\nV = 9000;       #volume of cinema hall(m**3)\n\n#Calculation\nT = 0.165*V/aS;     #reverberation time of hall(s)\nT = math.ceil(T*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"reverberation time of the hall is\",T, \"s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "reverberation time of the hall is 1.4143 s\n"
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.12, Page number 25"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 0.65;      #average absorption coefficient(Sabine/m**2)\nV = 13500;       #volume of auditorium(m**3)\nT = 1.2;         #reverberation time of hall(s)\n\n#Calculation\nS = 0.165*V/(a*T);     #reverberation time of hall(s)\nS = math.ceil(S*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"total area of interior surface is\",S, \"m**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "total area of interior surface is 2855.8 m**2\n"
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.13, Page number 25"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nV = 15000;       #volume of cinema hall(m**3)\nT1 = 1.3;        #initial reverberation time of hall(s)\na1S1 = 300;      #number of chairs placed\n\n#Calculation\naS = 0.165*V/T1;         #total absorption of hall\nT2 = (0.165*V)/(aS+a1S1);      #reverberation time of hall after adding chairs(s)\nT2 = math.ceil(T2*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"reverberation time of the hall after adding chairs is\",T2, \"s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "reverberation time of the hall after adding chairs is 1.1231 s\n"
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.14, Page number 26"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#Variable declaration\nv = 1440;         #velocity of ultrasonic waves(m/s)\nt = 0.5;         #time elapsed(s)\n\n#Calculation\nd = v*t;      #distance travelled(m)\nd1 = d/2;     #depth of submarine(m)\n\n#Result\nprint \"depth of the submerged submarine is\",int(d1), \"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 360 m\n"
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.15, Page number 26"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 0.4;        #distance between 2 constructive antinodes(mm)\nnew = 1.5;      #frequency of crystal(MHz)\n \n#Calculation\nnew = new*10**6;        #frequency of crystal(Hz)\nd = d*10**-3;     #distance between 2 constructive antinodes(m)\n#distance between 2 antinodes is given by lamda/2\nlamda = 2*d;      #wavelength of ultrasonic waves(m)\nv = new*lamda;       #velocity of waves(m/s)\n\n#Result\nprint \"velocity of waves is\",int(v), \"m/s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "velocity of waves is 1200 m/s\n"
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 1.16, Page number 26"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nl = 40;     #length of iron rod(mm)\nE = 11.5*10**10;      #Young's modulus(N/m**2)\nrho = 7250;   #density of pure iron(kg/m**3)\n\n#Calculation\nl = l*10**-3;     #length of iron rod(m)\nnew = (1/(2*l))*math.sqrt(E/rho);     #natural frequency of the rod(Hz)\nnew = new*10**-3;             #natural frequency of the rod(kHz)\nnew=math.ceil(new*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"depth of the submerged submarine is\",new, \"kHz\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "depth of the submerged submarine is 49.785 kHz\n"
-      }
-     ],
-     "prompt_number": 18
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter10.ipynb b/Engineering_Physics/Chapter10.ipynb
deleted file mode 100755
index 051ee9c1..00000000
--- a/Engineering_Physics/Chapter10.ipynb
+++ /dev/null
@@ -1,62 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter10"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "10: Dielectric Materials"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 10.1, Page number 289"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nepsilon_r = 1.0000684;            #dielectric constant\nN = 2.7*10**25;                   #number of atoms(per m**3)\nepsilon0 = 8.85*10**-12;          #permittivity of free space\n\n#Calculation\nalpha_e = epsilon0*(epsilon_r-1)/N;       #electronic polarizability(Fm**2)\n\n#Result\nprint \"electronic polarizability is\",alpha_e,\"Fm**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electronic polarizability is 2.242e-41 Fm**2\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 10.2, Page number 290"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nepsilon_r = 1.0024;            #relative permittivity\nN = 2.7*10**25;                   #number of atoms(per m**3)\nepsilon0 = 8.85*10**-12;          #permittivity of free space\n\n#Calculation\nalpha_e = epsilon0*(epsilon_r-1)/N;       #electronic polarizability(Fm**2)\n\n#Result\nprint \"electronic polarizability is\",alpha_e,\"Fm**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electronic polarizability is 7.86666666667e-40 Fm**2\n"
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter2.ipynb b/Engineering_Physics/Chapter2.ipynb
deleted file mode 100755
index fff10b22..00000000
--- a/Engineering_Physics/Chapter2.ipynb
+++ /dev/null
@@ -1,84 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter2",
-  "signature": "sha256:ac80f9dfe1725f11a5d4ce0fbda5ffed825d99c680f116629e5e3fcb8b69c198"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "2: Lasers"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 2.1, Page number 52"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590;        #wavelength(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\nk = 1.38*10**-23;       #boltzmann's constant\nT = 523;                #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9;      #wavelength(m)      \n#n1byn2 = math.exp(-(E2-E1)/(k*T))\n#but E2-E1 = h*new and new = c/lamda\n#therefore n1byn2 = math.exp(-h*c/(lamda*k*T))\nn1byn2 = math.exp(-h*c/(lamda*k*T));\n\n#Result\nprint \"relative population of Na atoms is\",n1byn2",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "relative population of Na atoms is 5.36748316686e-21\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 2.2, Page number 53"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590;        #wavelength(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\nk = 1.38*10**-23;       #boltzmann's constant\nT = 523;                #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9;      #wavelength(m)      \n#n21dashbyn21 = 1/(math.exp(h*new/(k*T))-1)\n#but new = c/lamda\n#therefore n21dashbyn21 = 1/(math.exp(h*c/(lamda*k*T))-1)\nA = math.exp(h*c/(lamda*k*T))-1;\nn21dashbyn21 = 1/A;    \n\n#Result\nprint \"ratio of stimulated to spontaneous emission is\",n21dashbyn21\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "ratio of stimulated to spontaneous emission is 5.36748316686e-21\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 2.3, Page number 53"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 632.8;        #wavelength of laser(nm)\nh = 6.625*10**-34;       #planck's constant\nc = 3*10**8;            #velocity of light(m/s)\np = 3.147;              #output power(mW)\n\n#Calculation\np = p*10**-3;          #output power(W)\nlamda = lamda*10**-9;      #wavelength(m)      \nnew = c/lamda;             #frequency(Hz)\nE = h*new;                 #energy of each photon(J)\nEm = p*60;                 #energy emitted per minute(J/min)\nN = Em/E;                  #number of photons emitted per second\n\n#Result\nprint \"number of photons emitted per second is\",N",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "number of photons emitted per second is 6.01183879245e+17\n"
-      }
-     ],
-     "prompt_number": 3
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter3.ipynb b/Engineering_Physics/Chapter3.ipynb
deleted file mode 100755
index 9e2d3109..00000000
--- a/Engineering_Physics/Chapter3.ipynb
+++ /dev/null
@@ -1,83 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter3"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "3: Fibre Optics and Applications"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 3.1, Page number 84"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nn0 = 1;            #refractive index of air\na = 180/math.pi;        #conversion factor of radian to degree\n\n#Calculation\nNA = math.sqrt((n1**2)-(n2**2));     #numerical aperture\nNA=math.ceil(NA*10)/10;   #rounding off to 1 decimal\nalpha_m = math.asin(NA/n0);         #acceptance angle(radian)\nalpha_m = alpha_m*a;                #acceptance angle(degrees)\nalpha_m=math.ceil(alpha_m*10**2)/10**2;   #rounding off to 2 decimals\nphi_m = math.asin(NA/n1);           #phase angle(radian)\nphi_m = phi_m*a;                    #phase angle(degrees)\nphi_m=math.ceil(phi_m*10**2)/10**2;   #rounding off to 2 decimals\ntheta_c = math.asin(n2/n1);         #critical angle(radian)\ntheta_c = theta_c*a;                #critical angle(degrees)\ntheta_c=math.ceil(theta_c*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"numerical aperture is\",NA\nprint \"acceptance angle is\",alpha_m,\"degrees\"\nprint \"phase angle is\",phi_m,\"degrees\"\nprint \"critical angle is\",theta_c,\"degrees\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "numerical aperture is 0.3\nacceptance angle is 17.46 degrees\nphase angle is 11.54 degrees\ncritical angle is 78.522 degrees\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 3.2, Page number 85"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nc = 3*10**8;       #velocity of light(m/sec)\n\n#Calculation\ndeltatbyL = (n1/n2)*((n1-n2)/c);\n\n#Result\nprint \"pulse broadening per unit length is\",deltatbyL,\"s/m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "pulse broadening per unit length is 1.02040816327e-10 s/m\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 3.3, Page number 85"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nphi_m = 11.54;       #phase angle(degrees)\na = 0.5*10**-4;\nx = math.pi/180;       #conversion factor from degrees to radians\n\n#Calculation\nphi_m = phi_m*x;      #phase angle(radian)\nL = a/math.tan(phi_m);      #length(m)\nn = 1/(2*L);          #total number of internal reflections(m-1)\n\n#Result\nprint \"alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\"\nprint \"alpha = alpha_m rays have\",int(n),\"m-1 internal reflections\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\nalpha = alpha_m rays have 2041 m-1 internal reflections\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter4.ipynb b/Engineering_Physics/Chapter4.ipynb
deleted file mode 100755
index 5651b165..00000000
--- a/Engineering_Physics/Chapter4.ipynb
+++ /dev/null
@@ -1,209 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter4"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "4: Quantum Physics"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.1, Page number 117"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.62*10**-34;     #planck's constant\nlamda = 1.2;          #wavelength of photon(Angstrom)\ne = 1.6*10**-19;      #conversion factor from J to eV\n\n#Calculation\nlamda = lamda*10**-10;       #wavelength of photon(m)\nE = (h*c)/(lamda*e);         #energy of photon(eV)\nE=math.ceil(E*10)/10;   #rounding off to 1 decimal\np = h/lamda;            #momentum of photon(kg m/s)\n\n#Result\nprint \"energy of the photon is\",E,\"eV\"\nprint \"momentum of the photon is\",p,\"kg m/s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "energy of the photon is 10343.8 eV\nmomentum of the photon is 5.51666666667e-24 kg m/s\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.2, Page number 117"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.625*10**-34;     #planck's constant\nnew = 900;             #frequency(kHz)\nE1 = 10;               #power radiated(kW)\n\n#Calculation\nE1 = E1*10**3;         #power radiated(W)\nnew = new*10**3;       #frequency(Hz)\nE = h*new;         #energy of photon(J)\nN = E1/E;          #number of photons emitted \n\n#Result\nprint \"number of photons emitted per second is\",N",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "number of photons emitted per second is 1.67714884696e+31\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.3, Page number 118"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.63*10**-34;     #planck's constant\nlamda = 5893;         #wavelength of photon(Angstrom)\nE1 = 100;             #power of lamp(W) \n\n#Calculation\nlamda = lamda*10**-10;       #wavelength of photon(m)\nE = h*c/lamda;         #energy of photon(J)\nN = E1/E;          #number of photons emitted \n\n#Result\nprint \"number of photons emitted per second is\",N\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "number of photons emitted per second is 2.96279537456e+20\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.4, Page number 118"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nc = 3*10**8;       #velocity of light(m/sec)\nh = 6.6*10**-34;     #planck's constant\nm0 = 9.1*10**-31;        #mass of photon(kg)\ntheta = 30;              #viewing angle(degrees)\nlamda = 2.8*10**-10;         #wavelength of photon(m)\n\n#Calculation\nx = math.pi/180;       #conversion factor from degrees to radians\ntheta = theta*x;       #viewing angle(radian) \nlamda_dash = (2*h*(math.sin(theta/2))**2/(m0*c))+lamda;        #wavelength of scattered radiation(m)\nlamda_dash = lamda_dash*10**10;           #wavelength of scattered radiation(Angstrom)\nlamda_dash=math.ceil(lamda_dash*10**5)/10**5;   #rounding off to 5 decimals\n\n#Result\nprint \"wavelength of scattered radiation is\",lamda_dash,\"Angstrom\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "wavelength of scattered radiation is 2.80324 Angstrom\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.5, Page number 119"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.6*10**-34;     #planck's constant\nm = 0.040;        #mass of bullet(kg)\nv = 1;            #speed of bullet(km/s)\n\n#Calculation\nv = v*10**3;      #speed of bullet(m/s)\np = m*v;          #momemtun of bullet(kg m/s)\nlamda = h/p;      #deBroglie wavelength(m)\nlamda = lamda*10**10;     #deBroglie wavelength(Angstrom)\n\n#Result\nprint \"deBroglie wavelength is\",lamda,\"Angstrom\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "deBroglie wavelength is 1.65e-25 Angstrom\n"
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.6, Page number 119"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 1;               #lowest energy state\na = 0.1;             #width of box(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.602*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of particle(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE = (n**2)*(h**2)/(8*m*(a**2));      #energy of particle(J)\nE_eV = E/e;             #energy of particle(eV)\nE_eV=math.ceil(E_eV*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"energy of particle is\",E,\"J or\",E_eV,\"eV\" ",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "energy of particle is 6.02231407794e-18 J or 37.6 eV\n"
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.7, Page number 120"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 1;               #lowest energy state\na = 4;             #width of well(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.6025*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of electron(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE = (n**2)*(h**2)/(8*m*(a**2));      #energy of particle(J)\nE_eV = E/e;             #energy of particle(eV)\nE_eV=math.ceil(E_eV*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"minimum energy of electron is\",E,\"J or\",E_eV,\"eV\" ",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "minimum energy of electron is 3.76394629871e-21 J or 0.0235 eV\n"
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.8, Page number 120"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1;               #lowest energy state\nn2 = 6;               #for 6th excited state\na = 0.1;             #width of box(nm)\nh = 6.625*10**-34;     #planck's constant\ne = 1.602*10**-19;       #conversion factor from J to eV\nm = 9.11*10**-31;        #mass of electron(kg)\n\n#Calculation\na = a*10**-9;        #width of box(m)\nE1 = (n1**2)*(h**2)/(8*m*(a**2));      #energy of electron in ground state(J)\nE6 = (n2**2)*(h**2)/(8*m*(a**2));      #energy of electron in excited state(J)\nE = E6-E1;                          #energy required to excite the electron(J)\nE_eV = E/e;             #energy required to excite the electron(eV)\nE_eV=math.ceil(E_eV*10)/10;   #rounding off to 1 decimal\n\n#Result\nprint \"energy required to excite the electron is\",E,\"J or\",E_eV,\"eV\" \nprint \"answer for energy in eV given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "energy required to excite the electron is 2.10780992728e-16 J or 1315.8 eV\nanswer for energy in eV given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 4.9, Page number 121"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nh = 6.625*10**-34;     #planck's constant\nc = 3*10**8;       #velocity of light(m/sec)\nm0 = 9.11*10**-31;        #rest mass of electron(kg)\nphi = 90;              #angle of scattering(degrees)\nx = math.pi/180;       #conversion factor from degrees to radians\n\n#Calculation\nphi = phi*x;           ##angle of scattering(radian)\ndelta_lamda = h*(1-math.cos(phi))/(m0*c);         #change in wavelength(m)\n\n#Result\nprint \"change in wavelength of X-ray photon is\",delta_lamda,\"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "change in wavelength of X-ray photon is 2.42407610684e-12 m\n"
-      }
-     ],
-     "prompt_number": 9
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter5.ipynb b/Engineering_Physics/Chapter5.ipynb
deleted file mode 100755
index ba6e0e69..00000000
--- a/Engineering_Physics/Chapter5.ipynb
+++ /dev/null
@@ -1,152 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter5"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "5: Crystal Physics"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.1, Page number 149, theoretical"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.2, Page number 150"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 8;          #number of atoms per cell\na = 5.43*10**-8;       #lattice constant(cm)\nw = 28.1;              #atomic weight(gm)\nN = 6.02*10**23;       #avagadro number\n\n#Calculation\nac = n/(a**3);         #atomic concentration(atoms/cm**3)\nd = ac*w/N;            #density of Si(g/cm**3)\nd=math.ceil(d*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"density of Si is\",d,\"g/cm**3\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "density of Si is 2.333 g/cm**3\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.3, Page number 151"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\na = 5;       #lattice constant(Angstrom)\n\n#Calculation\na = a*10**-10;         #lattice constant(m)\n#to calculate the planar concentration, only equilateral triangular region is considered of length a*math.sqrt(2) and height a*math.sqrt(3/2)\nl = a*math.sqrt(2);           #length of face diagonal(m)\nh = a*math.sqrt(3/2);         #height of triangle(m)\nA = l*h/2;                    #area of shaded portion(m**2)\n#every atom at the corner contributes 1/6 to this area.\nn111 = (3/6)*(1/A);           #planar concentration(atoms/m**2)\n\n#Result\nprint \"surface density of atoms is\",n111,\"atoms/m**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "surface density of atoms is 2.30940107676e+18 atoms/m**2\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.4, Page number 152"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 4.049;       #lattice constant(Angstrom)\nh = 2;\nk = 2;\nl = 0;           #miller indices of(2 2 0)\n\n#Calculation\nd = a/math.sqrt(h**2+k**2+l**2);        #spacing of planes(Angstrom)\nd=math.ceil(d*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"spacing of planes is\",d,\"Angstrom\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "spacing of planes is 1.432 Angstrom\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.5, Page number 152"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nd110 = 2.03;       #distance between planes(Angstrom)\nh = 1;\nk = 1;\nl = 0;           #miller indices of(1 1 0)\n\n#Calculation\na = d110*math.sqrt(h**2+k**2+l**2);        #size of unit cell(Angstrom)\na=math.ceil(a*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"size of unit cell is\",a,\"Angstrom\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "size of unit cell is 2.871 Angstrom\n"
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.6, Page number 152"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\na = 5.64;       #lattice constant(Angstrom)\nh1 = 1;\nk1 = 0;\nl1 = 0;           #miller indices of(1 0 0)\nh2 = 1;\nk2 = 1;\nl2 = 0;           #miller indices of(1 1 0)\nh3 = 1;\nk3 = 1;\nl3 = 1;           #miller indices of(1 1 1)\n\n#Calculation\nd100 = a/math.sqrt(h1**2+k1**2+l1**2);        #spacing of planes[100](Angstrom)\nd110 = a/math.sqrt(h2**2+k2**2+l2**2);        #spacing of planes[110](Angstrom)\nd111 = a/math.sqrt(h3**2+k3**2+l3**2);        #spacing of planes[111](Angstrom)\nd111=math.ceil(d111*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"spacing of plane [100] is\",d100,\"Angstrom\"\nprint \"spacing of plane [110] is\",round(d110),\"Angstrom\"\nprint \"spacing of plane [111] is\",d111,\"Angstrom\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "spacing of plane [100] is 5.64 Angstrom\nspacing of plane [110] is 4.0 Angstrom\nspacing of plane [111] is 3.26 Angstrom\n"
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 5.7, Page number 153"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nr = 1.605;         #radius of atom(Angstrom)\n\n\n#Calculation\nr = r*10**-10;      #radius of atom(m)\na = 2*r;        #size of unit cell(m)\nc = a*math.sqrt(8/3);\nV = 3*math.sqrt(3)*a**2*c/2;       #volume of unit cell(m**3)\n\n#Result\nprint \"volume of unit cell is\",V,\"m**3\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "volume of unit cell is 1.40330266432e-28 m**3\n"
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter6.ipynb b/Engineering_Physics/Chapter6.ipynb
deleted file mode 100755
index 768ed817..00000000
--- a/Engineering_Physics/Chapter6.ipynb
+++ /dev/null
@@ -1,356 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter6"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "6: Conducting Materials"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.1, Page number 170"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nm = 9.1*10**-31;          #mass of electron\nvf = 1*10**6;             #Fermi velocity(m/s)\ne = 1.6*10**-19;          #conversion factor from J to eV\n\n#Calculation\nEF = m*(vf**2)/(2*e);         #Fermi energy(eV)\nEF=math.ceil(EF*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Fermi energy is 2.85 eV\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.2, Page number 170"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nEF0 = 7.04;               #Fermi energy at 0K(eV)\nT = 300;                  #temperature(K)\nk = 1.38*10**-23;         #boltzmann constant\ne = 1.6*10**-19;          #conversion factor from J to eV\n\n#Calculation\nEF = EF0*(1-(((math.pi**2)/12)*(k*T/(EF0*e))**2));            #Fermi energy(eV)\nEF=math.ceil(EF*10**5)/10**5;   #rounding off to 5 decimals\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Fermi energy is 7.03993 eV\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.3, Page number 171"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 2.7*10**3;          #density of Al(kg/m**3)\nMat = 27;               #atomic weight of Al\ntow = 10**-14;          #relaxation time(sec)\nNa = 6.022*10**23;       #avagadro constant\na = 3*10**3;             #number of free electrons per atom\ne = 1.6*10**-19;         #charge of electron\nme = 9.1*10**-31;        #mass of electron\n\n#Calculation\nn = d*Na*a/Mat;          #concentration of atoms(per m**3)\nsigma = n*e**2*tow/me;          #conductivity(ohm m)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"conductivity of Al is\",sigma,\"*10**7 ohm m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "conductivity of Al is 5.0824 *10**7 ohm m\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.4, Page number 171"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nsigma = 5.87*10**7;         #electrical conductivity(per ohm m)\nK = 390;                    #thermal conductivity(W/mK)\nT = 20;                    #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nL = K/(sigma*T);          #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"Lorentz number is\",L,\"W ohm/K**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Lorentz number is 2.26756051189e-08 W ohm/K**2\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.5, Page number 172"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nd = 8900;          #density of Cu(kg/m**3)\nMat = 63.5;               #atomic weight of Cu\ntow = 10**-14;          #relaxation time(sec)\nNa = 6.022*10**23;       #avagadro constant\na = 1*10**3;             #number of free electrons per atom\ne = 1.6*10**-19;         #charge of electron\nme = 9.1*10**-31;        #mass of electron\n\n#Calculation\nn = d*Na*a/Mat;          #concentration of atoms(per m**3)\nsigma = n*e**2*tow/me;          #electrical conductivity(ohm m)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**7 ohm m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electrical conductivity is 2.3745 *10**7 ohm m\n"
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.6, Page number 172"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.54*10**-8;         #resistivity(ohm m)\nEF = 5.5;                  #fermi energy(eV)\nme = 9.1*10**-31;          #mass of electron\nepsilon = 100;\ne = 1.6*10**-19;           #charge of electron\nn = 5.8*10**28;            #concentration of electrons(per m**3)\n\n#Calculation\ntow = me/(rho*n*e**2);        #relaxation time(sec)\nmew = e*tow/me;               #mobility of electrons(m**2/Vs)\nmew = mew*10**3;\nvd = e*tow*epsilon/me;        #drift velocity(m/s)\nvd=math.ceil(vd*10)/10;   #rounding off to 1 decimal\nEF = EF*e;                    #fermi energy((J)\nvF = math.sqrt(2*EF/me);           #fermi velocity(m/s)\nvf = vF*10**-6;\nvf=math.ceil(vf*10**3)/10**3;   #rounding off to 3 decimals\nlamda_m = vF*tow;                  #mean free path(m)\n\n#Result\nprint \"relaxation time of electrons is\",tow,\"sec\"\nprint \"mobility of electrons is\",mew,\"*10**-3 m**2/Vs\"\nprint \"drift velocity of electrons is\",vd,\"m/s\"\nprint \"drift velocity given in the book is wrong\"\nprint \"fermi velocity of electrons is\",vf,\"*10**6 m/s\"\nprint \"mean free path is\",lamda_m,\"m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "relaxation time of electrons is 3.97972178683e-14 sec\nmobility of electrons is 6.9973130318 *10**-3 m**2/Vs\ndrift velocity of electrons is 0.7 m/s\ndrift velocity given in the book is wrong\nfermi velocity of electrons is 1.391 *10**6 m/s\nmean free path is 5.53462691011e-08 m\n"
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.7, Page number 174"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.72*10**-8;          #electrical resistivity(ohm m)\nL = 2.26*10**-8;            #Lorentz number(ohm W/K**2)\nT = 27;                     #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nK = L*T/rho;          #thermal conductivity(W/mK)\n\n#Result\nprint \"thermal conductivity is\",int(K),\"W/mK\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "thermal conductivity is 394 W/mK\n"
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.8, Page number 174"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nsigma = 5.87*10**7;         #electrical conductivity(per ohm m)\nK = 390;                    #thermal conductivity(W/mK)\nT = 20;                    #temperature(C)\n\n#Calculation\nT = T+273;                #temperature(K)\nL = K/(sigma*T);          #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"Lorentz number is\",L,\"W ohm/K**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Lorentz number is 2.26756051189e-08 W ohm/K**2\n"
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.9, Page number 174"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nE_EF = 0.01;               #energy(eV)\ne = 1.6*10**-19;           #conversion factor from eV to J\nT = 200;                    #temperature(K)\nk = 1.38*10**-23;           #boltzmann constant(J/K)\n\n#Calculation\nE_EF = E_EF*e;            #energy(J)\nA = E_EF/(k*T);\nFofE = 1/(1+(math.exp(A)));           #value of F(E)\nFofE=math.ceil(FofE*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"value of F(E) is\",FofE",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "value of F(E) is 0.36\n"
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.10, Page number 175"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 4*10**-8;     #mean free path(m)\nn = 8.4*10**28;          #density(per m**3)\nvthbar = 1.6*10**6;        #average thermal velocity(m/s)\ne = 1.6*10**-19;         #charge of electron(c)\nm = 9.11*10**-31;        #mass of electron\n\n#Calculation\nsigma = n*e**2*lamda/(m*vthbar);        #electrical conductivity(ohm-1 m-1)\nsigma = sigma*10**-7;\nsigma=math.ceil(sigma*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**7 ohm-1 m-1\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electrical conductivity is 5.91 *10**7 ohm-1 m-1\n"
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.11, Page number 176"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ntow = 10**-14;         #relaxation time(sec)\nT = 300;               #temperature(K)\nn = 6*10**28;          #electron concentration(per m**3)\ne = 1.6*10**-19;         #charge of electron(c)\nme = 9.1*10**-31;        #mass of electron\nk = 1.38*10**-23;           #boltzmann constant(J/K)\n\n#Calculation\nsigma = n*e**2*tow/me;        #electrical conductivity(ohm-1 m-1)\nsigmaa = sigma*10**-7;\nsigmaa=math.ceil(sigmaa*100)/100;   #rounding off to 2 decimals\nK = 3*n*(k**2)*tow*T/(2*me);           #thermal conductivity(W/mK)\nK=math.ceil(K*10)/10;   #rounding off to 1 decimal\nL = K/(sigma*T);         #Lorentz number(W ohm/K**2)\n\n#Result\nprint \"electrical conductivity is\",sigmaa,\"*10**7 ohm-1 m-1\"\nprint \"thermal conductivity is\",K,\"W/mK\"\nprint \"Lorentz number is\",L,\"W ohm/K**2\"\nprint \"answer for thermal conductivity and Lorentz number given in the book are wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electrical conductivity is 1.69 *10**7 ohm-1 m-1\nthermal conductivity is 56.6 W/mK\nLorentz number is 1.11775173611e-08 W ohm/K**2\nanswer for thermal conductivity and Lorentz number given in the book are wrong\n"
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.12, Page number 177"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nn = 5.8*10**28;          #electron concentration(per m**3)\ne = 1.6*10**-19;         #charge of electron(c)\nm = 9.1*10**-31;        #mass of electron\nrho = 1.54*10**-8;       #resistivity of metal(ohm m)\n\n#Calculation\ntow = m/(n*rho*e**2);         #relaxation time(sec)\n\n#Result\nprint \"relaxation time is\",tow,\"sec\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "relaxation time is 3.97972178683e-14 sec\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.13, Page number 177"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nrho = 1.54*10**-8;         #resistivity(ohm m)\nE = 1;                  #electric field(V/cm)\nme = 9.1*10**-31;          #mass of electron\ne = 1.6*10**-19;           #charge of electron\nn = 5.8*10**28;            #concentration of electrons(per m**3)\n\n#Calculation\nE = E*10**2;            #electric field(V/m)\ntow = me/(rho*n*e**2);        #relaxation time(sec)\nvd = e*E*tow/me;        #drift velocity(m/s)\nvd=math.ceil(vd*10)/10;   #rounding off to 1 decimal\nmew = vd/E;               #mobility of electrons(m**2/Vs)\nmew = mew*10**2;\n\n#Result\nprint \"relaxation time of electrons is\",tow,\"sec\"\nprint \"drift velocity of electrons is\",vd,\"m/s\"\nprint \"mobility of electrons is\",mew,\"*10**-2 m**2/Vs\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "relaxation time of electrons is 3.97972178683e-14 sec\ndrift velocity of electrons is 0.7 m/s\nmobility of electrons is 0.7 *10**-2 m**2/Vs\n"
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.14, Page number 178"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nT = 300;                   #temperature(K)\nl = 2;                     #length of wire(m)\nR = 0.02;                  #resistance(ohm)\nI = 15;                    #current(amp)\nmew = 4.3*10**-3;          #mobility(m**2/Vs)\n\n#Calculation\nV = I*R;                   #voltage drop(V)\nE = V/l;                   #electric field(V/m)\nvd = mew*E;                #drift velocity(m/s)\nvd = vd*10**3;\nvd=math.ceil(vd*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"drift velocity of electrons is\",vd,\"*10**-3 m/s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "drift velocity of electrons is 0.65 *10**-3 m/s\n"
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.15, Page number 179"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nvf = 0.86*10**6;          #fermi velocity(m/s)\nm = 9.1*10**-31;          #mass of electron(kg)\ne = 1.6*10**-19;          #charge of electron(C)\nk = 1.38*10**-23;         #boltzmann constant\n\n#Calculation\nEF = m*vf**2/(2*e);       #fermi energy(eV)\nEF=math.ceil(EF*100)/100;   #rounding off to 2 decimals\nTF = EF*e/k;                  #fermi temperature(K)\n\n#Result\nprint \"Fermi energy is\",EF,\"eV\"\nprint \"Fermi temperature is\",int(TF),\"K\"\nprint \"answer for fermi temperature given in the book is wrong due to rounding off the value of EF\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Fermi energy is 2.11 eV\nFermi temperature is 24463 K\nanswer for fermi temperature given in the book is wrong due to rounding off the value of EF\n"
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 6.16, Page number 179"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nTF = 2460;            #fermi temperature(K)\nm = 9.11*10**-31;          #mass of electron(kg)\nk = 1.38*10**-23;         #boltzmann constant\n\n#Calculation\nvF = math.sqrt(2*k*TF/m);          #fermi velocity(m/s)\nvF = vF*10**-5;\nvF=math.ceil(vF*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"Fermi velocity is\",vF,\"*10**5 m/s\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Fermi velocity is 2.731 *10**5 m/s\n"
-      }
-     ],
-     "prompt_number": 16
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter7.ipynb b/Engineering_Physics/Chapter7.ipynb
deleted file mode 100755
index d6a7ab3d..00000000
--- a/Engineering_Physics/Chapter7.ipynb
+++ /dev/null
@@ -1,468 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter7",
-  "signature": "sha256:043709ddd748250fcd3232cc251c6d71d665f281189e172a4c8d9b59233bdcee"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "7: Semiconducting Materials"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.1, Page number 208"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nme = 9.11*10**-31;          #mass of electron(kg)\nepsilon_r = 13.2;  \nepsilon0 = 8.85*10**-12;\nh = 6.63*10**-34;\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nm_nc = 0.067*me;\nE = m_nc*e**4/(8*(epsilon0*epsilon_r*h)**2);       #energy(J)\nE = E/e;                #energy(eV)\nE = math.ceil(E*10**5)/10**5;   #rounding off to 5 decimals\nE_meV = E*10**3;        #energy(meV)\n\n#Result\nprint \"donor binding energy is\",E,\"eV or\",E_meV,\"meV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "donor binding energy is 0.00521 eV or 5.21 meV\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.2, Page number 208"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nimport numpy as np\n\n#Variable declaration\nNd = 10**16;         #donor concentration(atoms/cm**3)\nni = 1.5*10**10;        #concentration(per cm**3)\nT = 300;                #temperature(K)\nkT = 0.0259;\n\n#Calculation\nn0 = Nd;           #for Nd>>ni, assume n0=Nd\np0 = ni**2/n0;        #equilibrium hole concentration(per cm**3)\np0 = p0*10**-4;\nEF_Ei = kT*np.log(n0/ni);\nEF_Ei = math.ceil(EF_Ei*10**4)/10**4;   #rounding off to 4 decimals\n\n\n#Result\nprint \"equilibrium hole concentration is\",p0,\"*10**4 per cm**3\"\nprint \"value of EF-Ei is\",EF_Ei,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "equilibrium hole concentration is 2.25 *10**4 per cm**3\nvalue of EF-Ei is 0.3474 eV\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.3, Page number 209"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;          #charge of electron(C)\nNd = 10**14;              #donor density(atoms/cm**3)\nmew_n = 3900;\n\n#Calculation\nn = Nd;\nsigma = n*e*mew_n;        #conductivity(ohm-1 cm-1)\nrho = 1/sigma;            #resistivity(ohm cm)\nrho = math.ceil(rho*100)/100;   #rounding off to 2 decimals\n\n\n#Result\nprint \"resistivity of sample is\",rho,\"ohm cm\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "resistivity of sample is 16.03 ohm cm\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.4, Page number 209"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;          #charge of electron(C)\nn0 = 5*10**16;              #donor density(atoms/cm**3)\nmew_0 = 800;\nIx = 2;             #current(mA)\nBz = 5*10**-5;\nd = 200;            #thickness(micrometre)\n\n#Calculation\nIx = Ix*10**-3;          #current(A)\nd = d*10**-4;            #thickness(m)\nsigma = e*n0*mew_0;        #conductivity(ohm-1 cm-1)\nrho = 1/sigma;            #resistivity(ohm cm)\nrho = math.ceil(rho*10**4)/10**4;   #rounding off to 4 decimals\nRH = -1/(e*n0);          #Hall coefficient(cm**3/C)\nVH = Ix*Bz*RH/d;         #Hall voltage(V)\nVH = VH*10**5;\n\n\n#Result\nprint \"resistivity of sample is\",rho,\"ohm cm\"\nprint \"Hall coefficient is\",RH,\"cm**3/C\"\nprint \"Hall voltage is\",VH,\"*10**-5 V\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "resistivity of sample is 0.1563 ohm cm\nHall coefficient is -125.0 cm**3/C\nHall voltage is -62.5 *10**-5 V\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.5, Page number 210"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nT = 300;          #temperature(K)\nmew_n = 0.4;      #electron mobility(m**2/Vs)\nmew_p = 0.2;      #hole mobility(m**2/Vs)\nEg = 0.7;         #band gap(eV)\nme = 9.11*10**-31;       #mass of electron(kg)\nk = 1.38*10**-23;        #boltzmann constant\nT = 300;                 #temperature(K)\nh = 6.625*10**-34;\nkT = 0.0259;\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nmn_star = 0.55*me;           #electron effective mass(kg)\nmp_star = 0.37*me;           #hole effective mass(kg)\na = (2*math.pi*k*T/(h**2))**(3/2);\nb = (mn_star*mp_star)**(3/4);\nc = math.exp(-Eg/(2*kT));\nni = 2*a*b*c;     #intrinsic concentration(per m**3)\nsigma = ni*e*(mew_n+mew_p);               #intrinsic conductivity(per ohm m)\nsigma = math.ceil(sigma*10**4)/10**4;   #rounding off to 4 decimals\nrho = 1/sigma;                            #intrinsic resistivity(ohm m)\nrho = math.ceil(rho*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"intrinsic concentration is\",ni,\"per m**3\"\nprint \"intrinsic conductivity is\",sigma,\"per ohm m\"\nprint \"intrinsic resistivity is\",rho,\"ohm m\"\nprint \"answers given in the book are wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "intrinsic concentration is 1.02825111151e+19 per m**3\nintrinsic conductivity is 0.9872 per ohm m\nintrinsic resistivity is 1.013 ohm m\nanswers given in the book are wrong\n"
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.6, Page number 211"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\nNd = 10**16;           #donor concentration(per cm**3)\nni = 1.45*10**10;         #concentration(per cm**3)\nkT = 0.0259;\n\n#Calculation\n#ni = Nc*math.exp(-(Ec-Ei)/kT)\n#Nd = Nc*(math.exp(-(Ec-Efd)/kT)\n#dividing Nd/ni we get \nEFd_Ei = kT*np.log(Nd/ni);\nEFd_Ei = math.ceil(EFd_Ei*10**4)/10**4;   #rounding off to 4 decimals\n\n#Result\nprint \"Fermi energy is\",EFd_Ei,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Fermi energy is 0.3482 eV\n"
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.7, Page number 211, theoretical"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.8, Page number 212"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\nT = 300;          #temperature(K)\nmew_n = 0.36;      #electron mobility(m**2/Vs)\nmew_p = 0.17;      #hole mobility(m**2/Vs)\nrho = 2.12;         #resistivity(ohm m)\nme = 9.11*10**-31;       #mass of electron(kg)\nkT = 0.0259;\nh = 6.625*10**-34;\nk = 1.38*10**-23;        #boltzmann constant\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nmn_star = 0.55*me;           #electron effective mass(kg)\nmp_star = 0.37*me;           #hole effective mass(kg)\nsigma = 1/rho;               #conductivity(per ohm m)\nsigma = math.ceil(sigma*10**3)/10**3;   #rounding off to 3 decimals\nni = sigma/(e*(mew_n+mew_p));          #concentration of electrons(per m**3)\na = (2*math.pi*kT/(h**2))**(3/2);\nNc = 2*a*(mn_star**(3/2)); \nNv = 2*a*(mp_star**(3/2)); \nb = (Nc*Nv)**(1/2);\nEg = 2*kT*np.log(b/ni);\n\n#Result\nprint \"forbidden energy gap is\",Eg,\"eV\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "forbidden energy gap is 4.09465494989 eV\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.9, Page number 213"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nni = 2.4*10**19;       #concentration(per m**3)\nmew_n = 0.39;      #electron mobility(m**2/Vs)\nmew_p = 0.19;      #hole mobility(m**2/Vs)\ne = 1.6*10**-19;          #charge of electron(C)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);         #conductivity(per ohm m)\nsigma = math.ceil(sigma*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"conductivity of sample is\",sigma,\"ohm-1 m-1\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "conductivity of sample is 2.228 ohm-1 m-1\n"
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.10, Page number 214"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nEc = 0.3;          #initial position(eV)\nT1 = 300;           #initial temperature(K)\nT2 = 330;           #increased temperature\n\n#Calculation\n#Ec/T1 = Ec_EF330/T2\nEc_EF330 = Ec*T2/T1;        #new position of Fermi level(eV)\n\n#Result\nprint \"new position of Fermi level is\",Ec_EF330,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "new position of Fermi level is 0.33 eV\n"
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.11, Page number 214"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nk = 1.38*10**-23;         #boltzmann constant\nT = 300;           #temperature(K)\nme = 9.1*10**-31;        #mass of electron(kg)\nh = 6.63*10**-34;        #planck's constant\nEc_Ev = 1.1;             #energy gap(eV)\ne = 1.6*10**-19;         #charge of electron(C)\n\n#Calculation\nme_star = 0.31*me;\nA = (2*math.pi*k*T*me_star/(h**2))**(3/2);\nB = math.exp(-(Ec_Ev*e)/(2*k*T));\nni = A*B;                  #concentration in conduction band(per m**3)\n\n#Result\nprint \"intrinsic electron concentration is\",ni,\"per m**3\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "intrinsic electron concentration is 1.26605935487e+15 per m**3\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.12, Page number 214"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nRH = 0.55*10**-10;          #Hall coefficient(m**3/As)\nsigma = 5.9*10**7;          #conductivity(ohm-1 m-1)\n\n#Calculation\nmew = RH*sigma;              #drift mobility(m**2/Vs)\nmew = mew*10**3;\nmew = math.ceil(mew*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"drift mobility of electrons is\",mew,\"*10**-3 m**2/Vs\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "drift mobility of electrons is 3.25 *10**-3 m**2/Vs\n"
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.13, Page number 215"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nA = 6.022*10**23;           #avagadro constant\nd = 8.96*10**-9;            #density(kg/m**3)\nn = 9.932*10**14;           #no. of free electrons per atom\nsigma = 5.9*10**7;          #conductivity(ohm-1 m-1)\ne = 1.6*10**-19;            #electron charge(C)\nmew = 3.2*10**-3;           #drift mobility(m**2/Vs)\nw = 63.5;                   #atomic weight of Cu(kg)\n\n#Calculation\nni = sigma/(mew*e);         #conductivity(per m**3)\nN = A*d*n/w;                #concentration of free electrons in pure Cu\nAN = ni/N;                  #average number of electrons contributed per Cu atom\n\n#Result\nprint \"concentration of free electrons in pure Cu is\",N,\"per m**3\"\nprint \"average number of electrons contributed per Cu atom is\",int(AN)",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "concentration of free electrons in pure Cu is 8.43940339906e+28 per m**3\naverage number of electrons contributed per Cu atom is 1\n"
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.14, Page number 215"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\nRH = 3.66*10**-11;          #hall coefficient(m**3/As)\ne = 1.6*10**-19;            #electron charge(C)\nsigma = 112*10**7;          #conductivity(ohm-1 m-1)\n\n#Calculation\nn = 1/(e*RH);               #charge carrier density(per m**3)\nmew_n = sigma/(n*e);        #electron mobility(m**2/As)\nmew_n = math.ceil(mew_n*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"charge carrier density is\",n,\"per m**3\"\nprint \"electron mobility is\",mew_n,\"m**2/As\"\nprint \"answers given in the book are wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "charge carrier density is 1.70765027322e+29 per m**3\nelectron mobility is 0.041 m**2/As\nanswers given in the book are wrong\n"
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.15, Page number 216"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nB = 1.5;                    #magnetic field(T)\nI = 50;                     #current(Amp)\nn = 8.4*10**28;             #free electron concentration(per m**3)\nd = 0.2;                    #thickness of slab(cm)\n\n#Calculation\nd = d*10**-2;               #thickness of slab(m)\nVH = B*I/(n*e*d);           #hall voltage(V)\n\n#Result\nprint \"magnitude of Hall voltage is\",VH,\"V\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "magnitude of Hall voltage is 2.79017857143e-06 V\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.16, Page number 216"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nn = 2.5*10**19;             #free electron concentration(per m**3)\nmew_n = 0.39;               #electron mobility(m**2/Vs)\nmew_p = 0.19;               #hole mobility(m**2/Vs)\nL = 1;                      #length(cm)\nw = 1;                      #width(mm)\nt = 1;                      #thickness(mm)\n\n#Calculation\nL = L*10**-2;               #length(m)\nw = w*10**-3;               #width(m)\nt = t*10**-3;               #thickness(m)\nA = w*t;                    #area(m**2)\nsigma = n*e*(mew_n+mew_p);         #conductivity(ohm-1 m-1)\nR = L/(sigma*A);                   #resistance(ohm)\n\n#Result\nprint \"resistance of intrinsic Ge rod is\",int(R),\"ohm\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "resistance of intrinsic Ge rod is 4310 ohm\n"
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.17, Page number 216"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nimport numpy as np\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nEg = 1.12;                  #band gap(eV)\nme = 1;\nmn_star = 0.12*me;               #electron mobility(m**2/Vs)\nmp_star = 0.28*me;               #hole mobility(m**2/Vs)\nk = 1.38*10**-23;                #boltzmann constant\nT = 300;                         #temperature\n\n#Calculation\na = mp_star/mn_star;\nEF = (Eg/2)+((3*k*T/(4*e))*np.log(a));\nEF = math.ceil(EF*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"position of Fermi level is\",EF,\"eV\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "position of Fermi level is 0.577 eV\n"
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.18, Page number 217"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 1.5*10**16;            #intrinsic carrier density(per m**3)\nmew_n = 0.13;               #electron mobility(m**2/Vs)\nmew_p = 0.05;               #hole mobility(m**2/Vs)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);        #electrical conductivity\nsigma = sigma*10**4;\n\n#Result\nprint \"electrical conductivity is\",sigma,\"*10**-4 ohm-1 m-1\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "electrical conductivity is 4.32 *10**-4 ohm-1 m-1\n"
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.19, Page number 217"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\nfrom __future__ import division\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 2.15*10**-13;            #intrinsic carrier density(per cm**3)\nmew_n = 3900;               #electron mobility(cm**2/Vs)\nmew_p = 1900;               #hole mobility(cm**2/Vs)\n\n#Calculation\nsigmai = ni*e*(mew_n+mew_p);        #electrical conductivity(ohm-1 cm-1)\nrhoi = 1/sigmai;                    #intrinsic resistivity(ohm cm)\n\n#Result\nprint \"intrinsic resistivity is\",rhoi,\"ohm cm\"\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "intrinsic resistivity is 5.01202886929e+27 ohm cm\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.20, Page number 217"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nni = 2.1*10**19;            #intrinsic carrier density(per m**3)\nmew_n = 0.4;               #electron mobility(m**2/Vs)\nmew_p = 0.2;               #hole mobility(m**2/Vs)\n\n#Calculation\nsigma = ni*e*(mew_n+mew_p);        #electrical conductivity\n\n#Result\nprint \"intrinsic resistivity is\",sigma,\"ohm-1 m-1\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "intrinsic resistivity is 2.016 ohm-1 m-1\n"
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.21, Page number 218"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nV = 1.35;                   #voltage supply(V)\nI = 5;               #current(mA)\nb = 5;               #breadth(mm)\nd = 1;               #thickness(mm)\nL = 1;               #length(cm)\nH = 0.45;            #magnetic field(Wb/m**2)\nVy =20;              #Hall voltage(mV)\n\n#Calculation\nVy = Vy*10**-3;       #Hall voltage(V)\nL = L*10**-2;         #length(m)\nd = d*10**-3;         #thickness(m)\nb = b*10**-3;         #breadth(m)\nI = I*10**-3;         #current(A)\nR = V/I;              #resistance(ohm)\nA = b*d;              #area(m**2)\nrho = R*A/L;          #resistivity(ohm m)\nEy = Vy/d;            #Hall field(V/m)\nJx = I/A;           \na = Ey/(H*Jx);         #current density(m**3/C).Here a is 1/ne \nRH = a;               #Hall coefficient(m**3/C)\nRH = math.ceil(RH*10**4)/10**4;   #rounding off to 4 decimals\nmew_n = RH/rho;       #electron mobility(m**2/Vs)\nmew_n = math.ceil(mew_n*10**2)/10**2;   #rounding off to 2 decimals\n\n#Result\nprint \"Hall coefficient is\",RH,\"m**3/C\"\nprint \"electron mobility is\",mew_n,\"m**2/Vs\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Hall coefficient is 0.0445 m**3/C\nelectron mobility is 0.33 m**2/Vs\n"
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 7.22, Page number 219"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\ne = 1.6*10**-19;            #electron charge(C)\nIx = 200;               #current(A)\nBz = 1.5;               #magnetic field(Wb/m**2)\np = 8.4*10**28;         #electron concentration(per m**3)\nd = 1;               #thickness(mm)\n\n#Calculation\nd = d*10**-3;         #thickness(m)\nVH = Ix*Bz/(e*p*d);         #Hall potential(V)\nVH = VH*10**6;              #Hall potential(micro V)\n\n#Result\nprint \"Hall potential is\",int(VH),\"micro V\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "Hall potential is 22 micro V\n"
-      }
-     ],
-     "prompt_number": 22
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter8.ipynb b/Engineering_Physics/Chapter8.ipynb
deleted file mode 100755
index 54d83b1d..00000000
--- a/Engineering_Physics/Chapter8.ipynb
+++ /dev/null
@@ -1,125 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter8"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "8: Magnetic Materials"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 8.1, Page number 238"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nI = 12;          #current(Ampere)\nA = 7.5*10**-4       #area of loop(m**2)\n\n#Calculation\nM = I*A;         #magnetic moment(Am**2)\nM = M*10**3;\n\n#Result\nprint \"magnetic moment is\",M,\"*10**-3 Am**2\"\nprint \"magnetic moment is in opposite direction from the observer\"\nprint \"M is perpendicular to the plane\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "magnetic moment is 9.0 *10**-3 Am**2\nmagnetic moment is in opposite direction from the observer\nM is perpendicular to the plane\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 8.2, Page number 238"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nr = 0.5;         #radius of orbit(Angstrom)\ne = 1.6*10**-19;       #charge of electron(C)\nnew = 10**16;          #frequency(rps)\n\n#Calculation\nr = r*10**-10;         #radius of orbit(m)\nI = e*new;             #current(Ampere)\nA = math.pi*r**2;      #area enclosed(m**2)\nM = I*A;               #magnetic moment(Am**2)\n\n#Result\nprint \"magnetic moment is\",M,\"Am**2\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "magnetic moment is 1.25663706144e-23 Am**2\n"
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 8.3, Page number 239"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nmew_r = 5000;       #relative permeability\n\n#Calculation\nchi_m = mew_r-1;       #magnetic susceptibility\n\n#Result\nprint \"magnetic susceptibility is\",chi_m",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "magnetic susceptibility is 4999\n"
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 8.4, Page number 239"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nH = 1800;       #magnetic field(A/m)\nphi = 3*10**-5;         #magnetic flux(Wb)\nA = 0.2;           #cross sectional area(cm**2)\n\n#Calculation\nA = A*10**-4;      #cross sectional area(m**2)\nB = phi/A;         #magnetic flux density(Wb/m**2)\nmew = B/H;         #permeability(H/m)\nmew = mew*10**4;\nmew=math.ceil(mew*100)/100;   #rounding off to 2 decimals\n\n#Result\nprint \"permeability is\",mew,\"*10**-4 H/m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "permeability is 8.34 *10**-4 H/m\n"
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 8.5, Page number 239"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nB = 0.65;      #magnetic induction(Wb/m**2)\nrho = 8906;       #density(kg/m**3)\nM = 58.7;         #atomic weight\nmew0 = 4*math.pi*10**-7;\nmb = 9.27*10**-24;\nNa = 6.023*10**26;      #avagadro constant\n\n#Calculation\nN = rho*Na/M;         #number of atoms per unit volume(atoms/m**3)\nmew_r = B/(N*mew0);         #relative permeability(A/m**2)\nM = mew_r/mb;               #magnetic moment in mew_B \nM=math.ceil(M*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"magnetic moment is\",M,\"mew_B\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "magnetic moment is 0.611 mew_B\n"
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter9.ipynb b/Engineering_Physics/Chapter9.ipynb
deleted file mode 100755
index ff53dd34..00000000
--- a/Engineering_Physics/Chapter9.ipynb
+++ /dev/null
@@ -1,62 +0,0 @@
-{
- "metadata": {
-  "name": "Chapter9"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": "9: Superconducting Materials"
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 9.1, Page number 255"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nH0 = 6.5*10**4;         #magnetic field intensity(A/m)\nT = 4.2;                #temperature(K)\nTc = 7.18;              #critical temperature(K)\n\n#Calculation\nHc = H0*(1-((T**2)/(Tc**2)));        #critical magnetic field intensity(A/m)\nHc = Hc*10**-4;\nHc=math.ceil(Hc*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"critical magnetic field intensity is\",Hc,\"*10**4 A/m\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "critical magnetic field intensity is 4.276 *10**4 A/m\n"
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": "Example number 9.2, Page number 255"
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": "#importing modules\nimport math\n\n#Variable declaration\nTc1 = 4.185;                #critical temperature for M1(K)\nTc2 = 4.133;                #critical temperature for M2(K)\nM1 = 199.5;                 #isotopic mass\nalpha = 0.5;\n\n#Calculation\nA = math.pow(M1,alpha)*Tc1/Tc2;\nM2 = math.pow(A,1/alpha);       #isotopic mass\nM2=math.ceil(M2*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"isotopic mass is\",M2\nprint \"answer given in the book is wrong\"",
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": "isotopic mass is 204.552\nanswer given in the book is wrong\n"
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_1.ipynb b/Engineering_Physics/Chapter_1.ipynb
deleted file mode 100755
index 4dd3b7b8..00000000
--- a/Engineering_Physics/Chapter_1.ipynb
+++ /dev/null
@@ -1,2094 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 1: Interference"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.1, Page 1.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " # Given \n",
-      "l = 6.6e-7 # wavelength of light in meter\n",
-      "L = 1.32e-5 # coherence length in meter\n",
-      "\n",
-      "#Calculation\n",
-      "coherence_time = L / (3 * 10 ** 8)#calculation for coherence time\n",
-      "\n",
-      "#Result\n",
-      "print \"Coherence time = %.1e sec\"%coherence_time"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence time = 4.4e-14 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.2, Page 1.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "L = 2.945e-2 # coherence length in meter\n",
-      "\n",
-      "#Calculations\n",
-      "coherence_time = L / (3 * 10**8) # calculation for coherence time\n",
-      "n = L / l                         # calculation for number of oscillations \n",
-      "\n",
-      "#Results\n",
-      "print \"Coherence time = %.3e sec.\"%coherence_time\n",
-      "print \"No. of oscillations = %.2e\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence time = 9.817e-11 sec.\n",
-        "No. of oscillations = 4.99e+04\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.3, Page 1.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given\n",
-      "l = 6.058e-7 # wavelength of light in meter\n",
-      "L = 0.2 # coherence length in meter\n",
-      "\n",
-      "#Calculations\n",
-      "line_width = (l**2) / L#calculation for line width\n",
-      "f_spread = (3 * 10**8) / L# calculation for frequency spread\n",
-      "f = (3 * 10**8) / l       # calculation for frequency\n",
-      "f_stability = f_spread / f # calculation for frequency stability\n",
-      "coherence_time = L / (3 * 10 ** 8) # calculation for coherence time\n",
-      "\n",
-      "#Results\n",
-      "print(\"Coherence time = %.3e sec\"%coherence_time)\n",
-      "print(\"Line width = %.3e meter\"%line_width)\n",
-      "print(\"Frequency stability = %.1e\"%f_stability)  #incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence time = 6.667e-10 sec\n",
-        "Line width = 1.835e-12 meter\n",
-        "Frequency stability = 3.0e-06\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.4, Page 1.41"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lambda_D = 5.5e-13 # Doppler width of orange light in meter\n",
-      "l = 6.058e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "coherence_length = (l ** 2) / lambda_D# calculation for coherence light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Coherence length = %.4f meter\"%coherence_length)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence length = 0.6673 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.5, Page 1.41"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lambda1 = 5.461e-7 # wavelength of light emitted by mercury vapour lamp in meter\n",
-      "band_width1 = 6e8 # band width for mercury vapour lamp in Hz\n",
-      "lambda2 = 6.328e-7 # the operating wavelength of light for He Ne laser \n",
-      "band_width2 = 1e6 # band width for laser in Hz\n",
-      "\n",
-      "#Calculations\n",
-      "delta_lambda1 = (lambda1**2 * band_width1) / 3e8 # calculation for difference between two wavelength for mercury vapour\n",
-      "delta_L1 = lambda1**2 / delta_lambda1 # calculation for coherence length for mercury vapour lamp\n",
-      "delta_lambda2 = (lambda2**2 * band_width2) / 3e8 # calculation for difference between two wavelength for He Ne laser\n",
-      "delta_L2 = lambda2**2 / delta_lambda2 # calculation for coherence length for He Ne laser\n",
-      "R = delta_L1/delta_L2 # calculation for ratio of coherence length of mercury vapour lamp to the coherence length of He Ne laser\n",
-      "\n",
-      "#Result\n",
-      "print(\"The ratio of coherence length of mercury vapour lamp to the coherence length of He Ne laser = 1:%d\"%(1./R))\n",
-      "#Answer differes due to rounding-off values"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The ratio of coherence length of mercury vapour lamp to the coherence length of He Ne laser = 1:600\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.6, Page 1.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "band_width = 3000 # band width of laser in hertz\n",
-      " \n",
-      "#Calculation\n",
-      "coherence_length = (3 * 10 ** 8) / band_width#calculation for coherence length \n",
-      "\n",
-      "#Result\n",
-      "print(\"Coherence length of laser = %.f meter\"%(coherence_length))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence length of laser = 100000 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.7, Page 1.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given\n",
-      "l = 6.328e-7 # wavelength of monochromatic light in meter\n",
-      "t = 10**-10 # chopping time in sec\n",
-      "\n",
-      "#Calculations\n",
-      "coherence_length = (3 * 10 ** 8) * t # calculation for coherence length of monochromatic light \n",
-      "band_width = 1 / t # calculation for band width \n",
-      "line_width = ((l ** 2) * band_width) / (3 * 10 ** 8) # calculation for line width \n",
-      "\n",
-      "#Result\n",
-      "print(\"Coherence length of monochromatic light = %.e meter. \\nband width = %.f Hz. \\nline width = %.4f A.\"%(coherence_length, band_width, line_width*1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence length of monochromatic light = 3e-02 meter. \n",
-        "band width = 10000000000 Hz. \n",
-        "line width = 0.1335 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.8, Page 1.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given\n",
-      "l = 6.438e-7 # wavelength of red cadmium line in meter\n",
-      "L = 3.8e-1 # coherence length in meter\n",
-      "\n",
-      "#Calculations\n",
-      "coherence_time = L / (3 * 10 ** 8)# calculation for coherence time\n",
-      "spectral_line_width = (l**2) / L # calculation for spectral line width\n",
-      "\n",
-      "#Result\n",
-      "print(\"Coherence time of red cadmium line = %.3e sec. \\nSpectral line width = %.2e meter.\"%(coherence_time,spectral_line_width))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coherence time of red cadmium line = 1.267e-09 sec. \n",
-        "Spectral line width = 1.09e-12 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.9, Page 1.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "from sympy import *\n",
-      "\n",
-      "# Given \n",
-      "ratio = 16 # ratio of intensities of two waves\n",
-      "\n",
-      "#Calculation\n",
-      "a1 = sqrt(ratio) # by the formula amplitude = sqrt(intensity)\n",
-      "a2 = 1\n",
-      "R = ((a1 + a2) ** 2) / ((a1 - a2) ** 2)# calculation for ratio of maximum intensity with minimum intensity\n",
-      "R = nsimplify(R)\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of maximum intensity with minimum intensity =\",R"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of maximum intensity with minimum intensity = 25/9\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.10, Page 1.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d = 0.0001 # distance between two slits in meter\n",
-      "Beta = 0.005 # width of the fringes formed in meter\n",
-      "D = 1 # distance between slit and screen in meter\n",
-      "\n",
-      "#Calculation\n",
-      "l = (Beta * d) / D # calculation for wavelength of light = %e meter\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A. \"%(l*1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 5000 A. \n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.11, Page 1.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "alpha = pi / 180 # angle of bi prism in radian\n",
-      "mu = 1.5 # refractive index of biprism \n",
-      "a = 0.4 # distance of bi prism from slit in meter\n",
-      "b = 0.6 # distance of bi prism from screen in meter\n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "D = a + b # calculation for distance between slits and screen\n",
-      "fringe_width = (l * D) / (2 * a * (mu - 1) * alpha) # calculation for fringe width\n",
-      "\n",
-      "#Result\n",
-      "print(\"Fringe width = %.3e meter.\"%(fringe_width))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fringe width = 8.441e-05 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.12, Page 1.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "d1 = 4.05e-3 # distance between slits in first position in meter\n",
-      "d2 = 2.90e-3 # distance between slits in second position in meter\n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "D = 1 # distance between slit and screen\n",
-      "\n",
-      "#Calculations\n",
-      "d = sqrt(d1 * d2)# calculation for distance between fringe\n",
-      "fringe_width = (l * D) / d # calculation for fringe width\n",
-      "\n",
-      "#Result\n",
-      "print(\"Fringe width = %.3f mm\"%(fringe_width*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fringe width = 0.172 mm\n"
-       ]
-      }
-     ],
-     "prompt_number": 48
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.13, Page 1.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import floor\n",
-      "\n",
-      "# Given \n",
-      "fringe_width = 3.42e-4 # fringe width in meter\n",
-      "mu = 1.542 # refractive index of glass\n",
-      "Xn = 2.143e-3 # shift of central fringe in meter\n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculations\n",
-      "n = Xn / fringe_width # calculation for order of the fringe\n",
-      "t = (floor(n) * l) / (mu - 1) # calculation for thickness of the glass\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of glass sheet = %.2e meter. \"%t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of glass sheet = 6.52e-06 meter. \n"
-       ]
-      }
-     ],
-     "prompt_number": 49
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.14, Page 1.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "fringe_width = 9e-4 # fringe width in meter\n",
-      "a = 0.1 # distance of bi prism from slit in meter\n",
-      "b = 0.9 # distance of bi prism from screen in meter\n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "D = a + b # calculation for distance between slits and screen\n",
-      "d = (l * D) / fringe_width # calculation for distance between coherent sources\n",
-      "\n",
-      "#Result\n",
-      "print(\"Distance between coherent sources = %.2e meter. \"%d)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance between coherent sources = 6.55e-04 meter. \n"
-       ]
-      }
-     ],
-     "prompt_number": 50
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.15, Page 1.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi,degrees\n",
-      "\n",
-      "# Given \n",
-      "fringe_width = 0.0135 # fringe width in meter\n",
-      "a = 0.5 # distance of bi prism from slits in meter\n",
-      "b = 0.5 # distance of bi prism from screen in meter\n",
-      "mu = 1.5 # refractive index of bi prism \n",
-      "alpha = pi / 360 # angle of bi prism in radian \n",
-      "\n",
-      "#Calculations\n",
-      "D = a + b # calculation for distance between slits and screen \n",
-      "l = (2. * a * (mu - 1) * alpha * fringe_width) / D # calculation for wavelength of light = %e meter\n",
-      "\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A \"%(l*1e8))\n",
-      "#Answer differs due to rounding-off errors\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 5890 A \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.16, Page 1.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "a = 45 # distance between slit and bi prism in cm\n",
-      "alpha = pi / 180 # angle of bi prism in radian\n",
-      "Mu = 1.5 # refractive index of bi prism\n",
-      "fringe_width = 15.6e-3 # fringe width in meter \n",
-      "D = 90      #cm\n",
-      "\n",
-      "#Calculations\n",
-      "d2 = (2*a*(Mu-1)*alpha) # calculation for distance between screen and slit\n",
-      "l = (fringe_width * d2) / D # calculation for wavelength\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A.\"%(l/1e-8))\n",
-      "#Answer differs due to rounding-off errors"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 13614 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.17, Page 1.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "D = 1.20 # distance between source and eye piece in meter\n",
-      "Xn = 1.9e-2 # distance move by eye piece for 20 fringe in meter\n",
-      "n = 20 # no. of fringes\n",
-      "d = 6e-4 # distance between slits in meter \n",
-      "\n",
-      "#Calculation\n",
-      "l = (Xn * d) / (D * n)# calculation for wavelength\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A.\"%(l*1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 4750 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.18, Page 1.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import floor\n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 5.890e-7 # wavelength of first light in meter\n",
-      "lambda2 = 4.358e-7 # wavelength of second light in meter\n",
-      "n1 = 40 # no. of fringes observed in the field of in first case \n",
-      "\n",
-      "#Calculation\n",
-      "n2 = (n1 * lambda1) / lambda2 # by using formula n1*lambda1=n2*lambda2\n",
-      "\n",
-      "#Result\n",
-      "print(\"No. of fringes observed in field of view in second case = %d. \"%(floor(n2)))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of fringes observed in field of view in second case = 54. \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.19, Page 1.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos\n",
-      "\n",
-      "# Given \n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "Mu = 1.42 # refractive index of soap film \n",
-      "i = 0 # incidence angle in radian \n",
-      "r = 0 # refracted angle in radian\n",
-      "n = 1 # for smallest thickness\n",
-      "\n",
-      "#Calculations\n",
-      "t1 = ((2 * n - 1) * l) / (4 * Mu * cos(r)) # calculation for east thickness of soap film for bright fringe\n",
-      "t2 = (n * l) / (2 * Mu * cos(r)) # calculation for east thickness of soap film for dark fringe\n",
-      "\n",
-      "#Result\n",
-      "print(\"Least thickness of soap film -\\n (a) For bright fringe = %.3e mm. \\n (b) For dark fringe = %.3e mm.\"%(t1*1000,t2*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Least thickness of soap film -\n",
-        " (a) For bright fringe = 1.038e-04 mm. \n",
-        " (b) For dark fringe = 2.075e-04 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 97
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.20, Page 1.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,pi,sin,asin\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "Mu_o = 1.4 # refractive index of oil film \n",
-      "Mu_w = 1.33 # refractive index of water\n",
-      "i = pi / 6 # incidence angle in radian \n",
-      "n = 6 # no. of fringes seen\n",
-      "\n",
-      "#Calculation\n",
-      "r = asin(sin(i) / Mu_o) # calculation for angle of refraction\n",
-      "t = (n * l) / (2 * Mu_o * cos(r)) # calculation for thickness of film\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of oil film = %.3e mm.\"%(t*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of oil film = 1.351e-03 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 98
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.21, Page 1.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos\n",
-      "\n",
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "Mu = 1.463 # refractive index of soap film \n",
-      "i = 0 # incidence angle in radian \n",
-      "r = 0 # refracted angle in radian\n",
-      "n = 1 # for smallest thickness\n",
-      "\n",
-      "#Calculation\n",
-      "t = ((2 * n - 1) * l) / (4 * Mu * cos(r)) # calculation for least thickness of soap film for bright fringe\n",
-      "\n",
-      "#Result\n",
-      "print(\"Least thickness of soap film for bright fringe = %.3e mm. \"%(t*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Least thickness of soap film for bright fringe = 1.025e-04 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 99
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.22, Page 1.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,pi,sin\n",
-      "\n",
-      "# Given That\n",
-      "l = 5.89e-7 # wavelength of light \n",
-      "Mu_o = 1.46 # refractive index of oil film \n",
-      "i = pi / 6 # incidence angle in radian \n",
-      "n = 8 # no. of fringe is seen\n",
-      "\n",
-      "#Calculations\n",
-      "r = asin(sin(i) / Mu_o) # calculation for angle of refraction\n",
-      "t = (n * l) / (2 * Mu_o * cos(r)) # calculation for thickness of oil film\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of oil film = %.2e mm. \"%(t*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of oil film = 1.72e-03 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 100
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.23, Page 1.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,pi,floor\n",
-      "\n",
-      "# Given That\n",
-      "lambda1 = 4e-7 # max. wavelength of light in meter\n",
-      "lambda2 = 5e-7 # min. wavelength of light in meter\n",
-      "Mu = 1.4 # refractive index of soap film \n",
-      "i = pi / 4 # incidence angle in radian \n",
-      "t = 1e-5 # thickness of oil film in meter\n",
-      "\n",
-      "#Calculations\n",
-      "r = asin(sin(i) / Mu) # calculation for angle of refraction\n",
-      "n1 = (2 * Mu * t * cos(r)) / lambda1 # calculation for no. of dark bands seen in the case of max. wavelength \n",
-      "n2 = (2 * t * Mu * cos(r)) / lambda2 # calculation for no. of dark seen in the case of min. wavelength \n",
-      "n = floor(n1) - floor(n2) # claculation for no. of dark bands seen between wavelengths\n",
-      "\n",
-      "#Result\n",
-      "print(\"No. of dark bands seen between wavelengths = %d\"%n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of dark bands seen between wavelengths = 12\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.24, Page 1.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "Mu = 1.5 # refractive index of soap film  \n",
-      "r = pi / 3 # refracted angle in radian\n",
-      "n = 1 # for smallest thickness\n",
-      "\n",
-      "#Calculation\n",
-      "t = (n * l) / (2 * Mu * cos(r)) # calculation for least thickness of soap film for bright fringe\n",
-      "\n",
-      "#Result\n",
-      "print(\"Least thickness of soap film for bright fringe = %.3e meter \"%t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Least thickness of soap film for bright fringe = 3.927e-07 meter \n"
-       ]
-      }
-     ],
-     "prompt_number": 104
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.25, Page 1.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,pi,sin\n",
-      "\n",
-      "# Given That\n",
-      "lambda1 = 6.1e-7 # max. wavelength of light in meter\n",
-      "lambda2 = 6e-7 # min. wavelength of light in meter\n",
-      "Mu = 1.333 # refractive index of  film \n",
-      "i = pi / 4 # incidence angle in radian \n",
-      "\n",
-      "#Calculation\n",
-      "r = asin(sin(i) / Mu) # calculation for angle of refraction\n",
-      "n = lambda2 / (lambda1 - lambda2) # calculation for no. of bright band\n",
-      "t = (n * lambda1) / (2 * Mu * cos(r)) # calculation for thickness of the film\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of the film = %.2e meter \"%t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of the film = 1.62e-05 meter \n"
-       ]
-      }
-     ],
-     "prompt_number": 105
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.26, Page 1.49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos\n",
-      "\n",
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "Mu = 1.463 # refractive index of soap film \n",
-      "i = 0 # incidence angle in radian \n",
-      "r = 0 # refracted angle in radian\n",
-      "n = 1 # for smallest thickness\n",
-      "\n",
-      "#Calculation\n",
-      "t = ((2 * n - 1) * l) / (4 * Mu * cos(r)) # calculation for thickness of soap film\n",
-      "\n",
-      "#Result\n",
-      "print(\"\\n Least thickness of soap film for bright fringe = %.3e meter. \"%t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "\n",
-        " Least thickness of soap film for bright fringe = 1.025e-07 meter. \n"
-       ]
-      }
-     ],
-     "prompt_number": 106
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.27, Page 1.49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import cos,sin,asin,pi,degrees,radians\n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 6.1e-7 # max. wavelength of light in meter\n",
-      "lambda2 = 6e-7 # min. wavelength of light in meter\n",
-      "Mu = 4. / 3 # refractive index of film \n",
-      "i = asin(4. / 5) # incidence angle in radian \n",
-      "\n",
-      "#Calculation\n",
-      "r = asin(sin(i) / Mu)*180/pi # calculation for angle of refraction\n",
-      "n = lambda2 / (lambda1 - lambda2) # calculation for order of fringe\n",
-      "t = (n * lambda1) / (2 * Mu * cos(r*pi/180)) # calculation for thickness of film\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of the film = %.3e mm. \"%(t*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of the film = 1.716e-02 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 127
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.28, Page 1.50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.893e-7 # wavelenth of light in meter\n",
-      "n = 20 # no. of interference fringes are observed \n",
-      "Mu = 1 # refractive index of air\n",
-      "i = 0 # incidence angle in radian \n",
-      "r = 0 # refracted angle in radian \n",
-      "\n",
-      "#Calculation\n",
-      "t = (n * l) / (2 * Mu) # calculation for thickness of fringe\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of wire = %.3e mm. \"%(t*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of wire = 5.893e-03 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 128
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.29, Page 1.50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 6e-7 # wavelength of light in meter\n",
-      "Mu = 1 # refractive index of air film\n",
-      "l = 0.06e-3 # diameter of wire in meter\n",
-      "L = 0.15 # distance of wire from edge in meter\n",
-      "\n",
-      "#Calculation\n",
-      "theta = l / L #calculation for theta\n",
-      "fringe_width = (lamda * L)/ (2 * Mu * l) # calculation for fringe width\n",
-      "\n",
-      "#Result\n",
-      "print(\"Fringe width = %.1e mm.\"%fringe_width)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fringe width = 7.5e-04 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 140
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.30, Page 1.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 4.56e-7 # wavelength of light in meter\n",
-      "theta = 1.9e-4 # angle of wedge in radian \n",
-      "Mu = 1 # refractive index of air\n",
-      "\n",
-      "#Calculation\n",
-      "fringe_width = l / (2 * Mu * theta)# calculation for fringe width \n",
-      "\n",
-      "#Result\n",
-      "print(\"Fringe width = %.1f mm.\"%(fringe_width*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fringe width = 1.2 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.31, Page 1.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 6e-7 # wavelength of light in meter\n",
-      "Mu = 1 # refractive index of air film\n",
-      "l = 0.03*10**-3 # diameter of wire in meter\n",
-      "L = 0.15 # distance of wire from edge in meter\n",
-      "i = 0 # incidence angle in radian \n",
-      "r = 0 # refracted angle in radian \n",
-      "\n",
-      "#Calculation\n",
-      "theta = l / L # calculation for theta\n",
-      "fringe_width = lamda / (2 * Mu * theta) # calculation for fringe width \n",
-      "\n",
-      "#Result\n",
-      "print(\"Fringe width = %.1f mm.\"%(fringe_width*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fringe width = 1.5 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 141
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.32, Page 1.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.890e-7 # wavelength of light in meter\n",
-      "theta = 1e-2 # angle of wedge in radian \n",
-      "n = 12 # no. of dark fringe\n",
-      "Mu = 1 # refractive index of air\n",
-      "i = 0 # incidence angle in radian\n",
-      "r = 0 # refracted angle in radian\n",
-      "\n",
-      "#Calculatiom\n",
-      "x = ( n * l) / (2 * theta) # calculation for distance\n",
-      "\n",
-      "#Result\n",
-      "print(\"Distance = %.2f mm. \"%(x*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance = 0.35 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 142
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.33, Page 1.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "w = 2e-5 # fringe width in meter\n",
-      "Mu = 1.5 # refractive index of film\n",
-      "i = 0 # incidence angle in radian\n",
-      "r = 0 # refracted angle in radian\n",
-      "\n",
-      "#Calculation\n",
-      "theta = l / (2 * Mu * w)# calculation for the angle of the film\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angle of wedge = %.3f degree. \"%(theta * 180/pi))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of wedge = 0.525 degree. \n"
-       ]
-      }
-     ],
-     "prompt_number": 143
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      " Example 1.34, Page 1.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d1 = 5.9e-3 # diameter of 15th ring in meter\n",
-      "d2 = 3.36e-3 # diameter of 5th ring in meter\n",
-      "R = 1 # radius of the plano-convex lens in meter\n",
-      "\n",
-      "#Calculations\n",
-      "p = 15 - 5\n",
-      "l = ((d1**2) - (d2**2)) / (4 * p * R) # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A.\"%(l*1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 5880 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.35, Page 1.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d1 = 2e-3 # diameter of 10th ring in meter\n",
-      "d2 = 3e-3 # diameter of 20th ring in meter\n",
-      "f = 0.9 # focal length of the plano-convex lens in meter\n",
-      "mu = 1.5 # refractive index of lens\n",
-      "\n",
-      "#Calculations\n",
-      "p = 20 - 10\n",
-      "R = (f * (mu - 1)) # calculation for radius of convex surface of lens\n",
-      "l = ((d2**2) - (d1**2)) / (4 * p * R)\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f nm.\"%(l*1e9))\n",
-      "#Incorrect answer in the textbook\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 2778 nm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 145
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.36, Page 1.53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt \n",
-      "\n",
-      "# Given \n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "f = 1 # focal length of the plano-convex lens in meter\n",
-      "mu = 1.5 # refractive index of lens \n",
-      "n = 7 # no. of bright ring\n",
-      "\n",
-      "#Calculations\n",
-      "p = 20 - 10\n",
-      "R = (f * (mu - 1)) * 2 # calculation for radius of lens\n",
-      "D = sqrt(4 * n * l * R) # calculation for diameter of 7th ring \n",
-      "\n",
-      "#Result\n",
-      "print(\"Diameter of 7th bright ring = %.3e meter.\"%(D))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of 7th bright ring = 4.063e-03 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 146
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.37, Page 1.53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given That\n",
-      "lambda1 = 6e-7 # wavelength of first light in meter\n",
-      "lambda2 = 4.8e-7 # wavelength of second light in meter\n",
-      "r = 0.96 # radius of curvature of curved surface of lens in meter\n",
-      "\n",
-      "#Calculations\n",
-      "n = lambda2 / (lambda1 - lambda2) # calculation for order of fringe\n",
-      "D = sqrt(4 * (n + 1) * lambda2 * r) # calculation for diameter of ring\n",
-      "\n",
-      "#Result\n",
-      "print(\"Diameter of (n +1)th dark ring of lambda2. = %.2e meter.\"%D)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of (n +1)th dark ring of lambda2. = 3.04e-03 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 147
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.38, Page 1.54"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 6e-7 # wavelength of first light in meter\n",
-      "lambda2 = 5.9e-7 # wavelength of second light in meter\n",
-      "r = 0.9 # radius of curvature of curved surface of lens in meter\n",
-      "\n",
-      "#Calculations\n",
-      "n = lambda2 / (lambda1 - lambda2) # calculation for order of ring\n",
-      "D = sqrt(4 * (n + 1) * lambda1 * r) # calculation for diameter of ring\n",
-      "\n",
-      "#Result\n",
-      "print(\"Diameter of nth dark ring of lambda1 = %.4f meter.\"%D)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of nth dark ring of lambda1 = 0.0114 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 148
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.39, Page 1.54"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "D = 4e-3 # diameter of 7th brighter fringe in m\n",
-      "R = 1 # radius of curvature in m\n",
-      "n = 7 # for seventh brighter fringe\n",
-      "\n",
-      "#Calculation\n",
-      "mu = 2*(2*n-1)*l*R / D**2 # calculation for refractive index of liquid\n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of liquid = %.2f.\"%mu)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of liquid = 0.96.\n"
-       ]
-      }
-     ],
-     "prompt_number": 149
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.40, Page 1.54"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "D1 = 3e-3 # diameter of nth dark fringe when liquid is absent between the lens and the plate in m\n",
-      "D2 = 2.5e-3 # diameter of nth dark fringe when liquid is introduced between the lens and the plate in m\n",
-      "c = 3e8 # velocity of light in vacuum in m/sed\n",
-      "\n",
-      "#Calculations\n",
-      "mu = D1**2 / D2**2# calculation for refractive index\n",
-      "v = 3e8 / mu # calculation for velocity of light \n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of liquid = %.2f.\\n velocity of light in the liquid = %.2e m/sec.\"%(mu,v))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of liquid = 1.44.\n",
-        " velocity of light in the liquid = 2.08e+08 m/sec.\n"
-       ]
-      }
-     ],
-     "prompt_number": 150
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.41, Page 1.55"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "D = 5.1e-3 # diameter of 16th brighter fringe in m\n",
-      "R = 1 # radius of curvature in m\n",
-      "n = 16 # for sixteenth brighter fringe\n",
-      "\n",
-      "#Calculation\n",
-      "mu = 4*n*l*R / D**2 # calculation for refractive index of liquid\n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of liquid = %.2f\"%mu)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of liquid = 1.45\n"
-       ]
-      }
-     ],
-     "prompt_number": 170
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.42, Page 1.55"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 6.3e-7 # wavelength of light in meter\n",
-      "mu = 1.63 # refractive index of liquid \n",
-      "R = 0.9 # the radius of curvature of convex lens in meter\n",
-      "\n",
-      "#Calculation\n",
-      "r = sqrt(l*R/mu) # calculation for the radius of smallest dark ring\n",
-      "\n",
-      "#Result\n",
-      "print(\"The radius of smallest dark ring = %.2f mm.\"%(r*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The radius of smallest dark ring = 0.59 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 171
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.43, Page 1.55"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "r = 10./7 # ratio of nth ring diameter for two media\n",
-      "\n",
-      "#Calculation\n",
-      "R = (1/r)**2 # calculation for the ratio of refractive index of media\n",
-      "\n",
-      "#Result\n",
-      "print(\"The ratio refractive index of media = %.f:100.\"%(R*100))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The ratio refractive index of media = 49:100.\n"
-       ]
-      }
-     ],
-     "prompt_number": 173
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.44, Page 1.56"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "R = 0.9 # radius of curvature of the lower face of the lens in meter\n",
-      "D = 4.8e-3 # diameter of the 10th dark ring in meter\n",
-      "n = 10 # for 10th dark ring\n",
-      "\n",
-      "#Calculation\n",
-      "l = D**2 / (4 * n * R) # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A.\"%(l * 1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 6400 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 174
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.45, Page 1.56"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "r = 1./2 # ratio of 5th ring diameter \n",
-      "\n",
-      "#Calculatio\n",
-      "R = (1/r)**2 # calculation for refractive index of liquid\n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of liquid = %.f. \"%R)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of liquid = 4. \n"
-       ]
-      }
-     ],
-     "prompt_number": 175
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.46, Page 1.56"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given That\n",
-      "R = 1 # radius of curvature of lens of both side in meter\n",
-      "l = 5.4e-7 # wavelength of monochromatic light in meter\n",
-      "n1 = 5 # for 5th dark ring\n",
-      "n2 = 15 # for 10th dark ring\n",
-      "\n",
-      "#Calculation\n",
-      "r1 = sqrt((n1*l)/(1/R + 1/R)) # calculation for radius of 5th dark ring\n",
-      "r2 = sqrt((n2*l)/(1/R + 1/R)) # calculation for radius of 15th dark ring\n",
-      "d = r2 - r1 # calculation for distance between 5th and 15th dark ring\n",
-      "\n",
-      "#Result\n",
-      "print(\"Distance between 5th and 15th dark ring = %.3f cm.\"%(d * 100))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance between 5th and 15th dark ring = 0.085 cm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 177
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.47, Page 1.57"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "x = 2.5e-5 # distance moved by movable mirror in meter\n",
-      "t = 5e-5 # thickness of mica sheet in meter\n",
-      "\n",
-      "#Calculation\n",
-      "mu = x / t + 1 # calculation for refractive index of mica\n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of mica = %.1f\"%mu)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of mica = 1.5\n"
-       ]
-      }
-     ],
-     "prompt_number": 179
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.48, Page 1.57"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "x = 6e-5 # distance moved by movable mirror in meter\n",
-      "N = 200 # no. of fringes crossed the field of view \n",
-      "\n",
-      "#Calculation\n",
-      "l = (2 * x) / N # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.f A.\"%(l * 1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 6000 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 180
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.49, Page 1.57"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 50 # no. of bands crosses the line of observation \n",
-      "l = 5.896e-7 # wavelength of light in meter\n",
-      "mu = 1.4 # refractive index \n",
-      "\n",
-      "#Calculation\n",
-      "t = n*l / (2*(mu-1)) # calculation for thickness of the plate\n",
-      "\n",
-      "#Result\n",
-      "print(\"Thickness of the plate = %.2e m.\"%t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of the plate = 3.69e-05 m.\n"
-       ]
-      }
-     ],
-     "prompt_number": 181
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.50, Page 1.57"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 50 # no. of bands crosses the line of observation \n",
-      "lambda1 = 5.896e-7 # max. wavelength of light in meter\n",
-      "lambda2 = 5.89e-7 # min. wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "x = lambda1 * lambda2 /(lambda1 - lambda2) # calculation for the path difference\n",
-      "\n",
-      "#Result\n",
-      "print(\"The path difference = %.4f mm.\"%(x*10**3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The path difference = 0.5788 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 182
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.51, Page 1.58"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "x = 2.948e-5 # distance moved by movable mirror in meter\n",
-      "n = 100 # no. of fringes cross the field of view \n",
-      "\n",
-      "#Calculation\n",
-      "l = 2*x/n # calculation for wavelength of monochromatic light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of monochromatic light = %.f A.\"%(l * 1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of monochromatic light = 5896 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 183
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.52, Page 1.58"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lambda1 = 5.896e-7 # max. wavelength of light in meter\n",
-      "lambda2 = 5.89e-7 # min. wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "x = lambda1 * lambda2 /(2*(lambda1 - lambda2)) # calculation for the path difference\n",
-      "\n",
-      "#Result\n",
-      "print(\"The distance through which the movable mirror is move = %.3f mm.\"%(x*10**3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The distance through which the movable mirror is move = 0.289 mm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 184
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.53, Page 1.58"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "x = 2.945e-4 # distance moved by movable mirror in meter\n",
-      "l = 5.893e-7 # mean wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "delta_lambda = l**2 / (2*x) # calculation for difference between two wavelengths\n",
-      "\n",
-      "#Result\n",
-      "print(\"Difference between two wavelengths = %.3f A.\"%(delta_lambda*1e10))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Difference between two wavelengths = 5.896 A.\n"
-       ]
-      }
-     ],
-     "prompt_number": 185
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1.54, Page 1.58"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 140 # no. of shift in fringe\n",
-      "l = 5.46e-7 # wavelength of light in meter\n",
-      "t = 0.2 # length of tube in meter\n",
-      "\n",
-      "#Calculation\n",
-      "mu = (n*l)/(2*t) + 1 # calculation for refractive index of gas\n",
-      "\n",
-      "#Result\n",
-      "print(\"Refractive index of gas = %.5f\"%mu)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of gas = 1.00019\n"
-       ]
-      }
-     ],
-     "prompt_number": 188
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_10.ipynb b/Engineering_Physics/Chapter_10.ipynb
deleted file mode 100755
index 39a354b1..00000000
--- a/Engineering_Physics/Chapter_10.ipynb
+++ /dev/null
@@ -1,613 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 10: Electromagnetism"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.15, Page 10.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 2000 # flux lines enter in given volume  in Vm\n",
-      "n_ = 4000 # flux lines diverge from given volume in Vm\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculations\n",
-      "fi = n_ - n\n",
-      "q = e0 * fi\n",
-      "\n",
-      "#Result\n",
-      "print 'The total charge within volume(in C) = ',q"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The total charge within volume(in C) =  1.77e-08\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.16, Page 10.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 20000 # flux lines entering in given volume in Vm\n",
-      "n_ = 45000 # flux lines entering out from given volume in Vm\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculations\n",
-      "fi = n_ - n\n",
-      "q = e0 * fi\n",
-      "\n",
-      "#Result\n",
-      "print \"The total charge enclosed by closed surface is %.3e C\"%q"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The total charge enclosed by closed surface is 2.212e-07 C\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.17, Page 10.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "q = 13.5e-6 # charge enclosed at the centre of cube in C\n",
-      "l = 6 # length of the side of cube in cm\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculations\n",
-      "fi = q / e0\n",
-      "fi_ = fi / 6\n",
-      "q = e0 * fi\n",
-      "\n",
-      "#Results\n",
-      "print \"Electric flux through the whole volume of the cube is %.3e Nm^2/C\\nElectric flux through one face of the cube is %.2e Nm^2/C\"%(fi,fi_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Electric flux through the whole volume of the cube is 1.525e+06 Nm^2/C\n",
-        "Electric flux through one face of the cube is 2.54e+05 Nm^2/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.18, Page 10.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "q = 11 # charge enclosed at the centre of cube in C\n",
-      "l = 5 # length of the side of cube in cm\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculation\n",
-      "fi_ = (q / e0) / 6\n",
-      "\n",
-      "#Result\n",
-      "print \" Electric flux through each surface of the cube = %.2e Nm^2/C\"%fi_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Electric flux through each surface of the cube = 2.07e+11 Nm^2/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.19, Page 10.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "q = 1e-8 # charge uniformly spread over metallic sphere in C\n",
-      "r = .1 #radius of sphere in m\n",
-      "d = 7 # distance of a point from centre of the sphere in cm\n",
-      "d_ = .5 # distance of another point from centre of the sphere in m\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#calculations\n",
-      "E1 = (1 / (4 * pi * e0) * (q / r**2))\n",
-      "E2 = 0 #because sphere is metallic\n",
-      "E3 = (1 / (4 * pi * e0) * (q / d_**2))\n",
-      "\n",
-      "#Result\n",
-      "print \"Electric field intensity-\\n(1) On the surface of the sphere = %.e N/C\\n(2) At first point = %d N/C\\n(3)At second point = %.2e N/C\"%(E1,E2,E3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Electric field intensity-\n",
-        "(1) On the surface of the sphere = 9e+03 N/C\n",
-        "(2) At first point = 0 N/C\n",
-        "(3)At second point = 3.60e+02 N/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.20, Page 10.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "q = 1.6e-19 # charge on a proton in C\n",
-      "d = 1e-10 # distance of a point from proton in m\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculation\n",
-      "E = (1 / (4 * pi * e0)) * (q / d**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Electric field = %.2e V/m\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Electric field = 1.44e+11 V/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.21, Page 10.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "v = 1000 # potential through which alpha particle accelerated in V\n",
-      "q = 3.2e-19 # charge on an alpha particle in C\n",
-      "e0 = 8.85e-12 # electric permittivity of space\n",
-      "\n",
-      "#calculation\n",
-      "E = q * v\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy gained by alpha particle = %.1e J\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy gained by alpha particle = 3.2e-16 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.22, Page 10.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "q = 1.6e-19 # charge on a proton in C\n",
-      "d = 1e-10 # distance of a point from proton in m\n",
-      "d_ = 2e-11 # distance of another point from proton in m\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#calculations\n",
-      "v = (1 / (4 * pi * e0)) * (q / d)#calculation for potential at first point\n",
-      "E = -q * v#calculation for energy at first point in J\n",
-      "delta_v = (1 / (4 * pi * e0)) * q * ((1 / d_) - (1 / d))#calculation for potential difference between points\n",
-      "\n",
-      "#Result\n",
-      "print \"Potential energy at first point = %.1f eV\\nPotential difference between points = %.1f V\"%(E/q,delta_v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Potential energy at first point = -14.4 eV\n",
-        "Potential difference between points = 57.5 V\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.23, Page 10.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, ceil\n",
-      "\n",
-      "# Given \n",
-      "q = 1.5e-6 # charge in C\n",
-      "v = 30 # potential of a surface in V\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculation\n",
-      "r = (1 / (4 * pi * e0)) * (q / v)\n",
-      "\n",
-      "#Result\n",
-      "print \"Radius of equipotential surface = %d m\"%ceil(r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of equipotential surface = 450 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.24, Page 10.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "p = 3.8e26 # power radiated by sun in W\n",
-      "r = 7e8 # radius of sun in m\n",
-      "e0 = 8.85e-12 # permittivity of space\n",
-      "\n",
-      "#Calculation\n",
-      "s = p / (4 * pi * r**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"The value of poynting vector at the surface of the sun = %.3e W/m^2\"%s"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The value of poynting vector at the surface of the sun = 6.171e+07 W/m^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.25, Page 10.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#Given\n",
-      "Se = (2*4.2)/(60*10**-4)   #J/m^2-sec\n",
-      "c = 3*10**8                #m/s\n",
-      "res = 1.4*10**11           #m\n",
-      "rs = 7*10**7               #W/m^2\n",
-      "\n",
-      "#Calculations\n",
-      "Prad_e = Se/c\n",
-      "Ss = Se*((res/rs)**2)\n",
-      "Prad_s = Ss/c\n",
-      "\n",
-      "#Results\n",
-      "print \"Radiation pressure at the surface of the earth =%.2e N/m^2\"%Prad_e\n",
-      "print \"Radiation pressure at the surface of the sun =%.3e N/m^2\"%Prad_s"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radiation pressure at the surface of the earth =4.67e-06 N/m^2\n",
-        "Radiation pressure at the surface of the sun =1.867e+01 N/m^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.28, Page 10.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "s = 2 # energy received by the earth in cal/cm^2.min\n",
-      "e0 = 8.85e-12 # electric permittivity of space\n",
-      "mu0 = 1.2567e-6 # magnetic permittivity of space\n",
-      "c = 3e8 # speed of light in meter/sec\n",
-      "\n",
-      "#calculations\n",
-      "r = sqrt(mu0 / e0)\n",
-      "P = s*4.2/(60*1e-4)\n",
-      "E = sqrt(P*r)\n",
-      "H = E/r\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnitude of electric field vector = %.1f v/m\\nMagnitude of magnetic field vector = %.3f A/m\"%(E * sqrt(2),H*sqrt(2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnitude of electric field vector = 1027.2 v/m\n",
-        "Magnitude of magnetic field vector = 2.726 A/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.29, Page 10.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "H = 1 # magnitude of magnetic field vector A/m\n",
-      "e0 = 8.85e-12 # electric permittivity of space\n",
-      "mu0 = 1.2567e-6 # magnetic permittivity of space\n",
-      "c = 3e8 # speed of light in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "r = sqrt(mu0 / e0) # ratio of E,H\n",
-      "E = H * r\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnitude of electric field vector = %.2f v/m.\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnitude of electric field vector = 376.83 v/m.\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.31, Page 10.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "p = 1000 # power of lamp in W\n",
-      "d = 2 # distance of a point from lamp in meter\n",
-      "e0 = 8.85e-12 # electric permittivity of space\n",
-      "mu0 = 1.2567e-6 # magnetic permittivity of space\n",
-      "c = 3e8 # speed of light in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "s = p / (4 * pi * d**2) #calculation for \n",
-      "r = sqrt(mu0 / e0) # ratio of E,H\n",
-      "E = sqrt(s * r)#calculation for average value of intensity of electric field of radiation\n",
-      "\n",
-      "#Result\n",
-      "print \"Average value of the intensity of electric field of radiation = %.2f v/m.\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average value of the intensity of electric field of radiation = 86.58 v/m.\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10.32, Page 10.49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "k = 81 # relative permittivity of water \n",
-      "c = 3e8 # speed of light in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "mu = sqrt(k)\n",
-      "v = c / mu\n",
-      "\n",
-      "#Result\n",
-      "print \"Refractive index of distilled water is %d \\nSpeed of light in water is %.2e m/sec\"%(mu,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index of distilled water is 9 \n",
-        "Speed of light in water is 3.33e+07 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_11.ipynb b/Engineering_Physics/Chapter_11.ipynb
deleted file mode 100755
index 0cd9f3f6..00000000
--- a/Engineering_Physics/Chapter_11.ipynb
+++ /dev/null
@@ -1,1203 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 11: Theory of Relativity"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.5, Page 11.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "# Given \n",
-      "x = 100 # in meter\n",
-      "y = 10 # in meter\n",
-      "z = 5  # in meter\n",
-      "t = 1e-4 # in sec\n",
-      "# coordinates of point in frame F\n",
-      "v = 2.7e8 # velocity of frame F_ w.r.t. frame F in m/sed\n",
-      "c=3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "# according to Galilean transformation\n",
-      "x__ = x-v*t\n",
-      "y__=y\n",
-      "z__=z\n",
-      "t__=t\n",
-      "# according to Lorentz transformation\n",
-      "x_ = (x-v*t)/sqrt(1-(v/c)**2)\n",
-      "y_=y\n",
-      "z_=z\n",
-      "t_=(t-(v*x/c**2))/sqrt(1-(v/c)**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Coordinate of the event in reference frame F_ using \\n(a)Galilean transformation-x=%.f m, y=%.f m, z = %.f m, t = %.e sec\"%(x__,y__,z__,t__) \n",
-      "print \"(b)Lorentz transformation-x=%.f m,y =%.f m, z = %.f m, t=%.e sec \"%(x_,y_,z_,t_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Coordinate of the event in reference frame F_ using \n",
-        "(a)Galilean transformation-x=-26900 m, y=10 m, z = 5 m, t = 1e-04 sec\n",
-        "(b)Lorentz transformation-x=-61713 m,y =10 m, z = 5 m, t=2e-04 sec \n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.6, Page 11.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 4 # ratio of mass of particle to the rest mass\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / r)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of particle is %.e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of particle is 3e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.7, Page 11.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 1.2 # ratio of mass of particle to the rest mass\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / r)**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Speed of particle is %.3f c\"%(v/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of particle is 0.553 c\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.9, Page 11.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E = 2 # kinetic energy of electron in Mev\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / (1 + (1.6e-19 * 2e6) / (9.1e-31 * 3e8**2)))**2)\n",
-      "m = (9.1e-31) / sqrt(1 - (v / 3e8)**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Speed of electron is %.2f c\\nMass of electron is %.2e kg\"%(v/3e8,m)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of electron is 0.98 c\n",
-        "Mass of electron is 4.47e-30 kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.11, Page 11.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "r = 2.25 # ratio of mass of particle to the rest mass\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / r)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of particle is %.2e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of particle is 2.69e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.12, Page 11.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 2. # ratio of kinetic energy of body to its rest mass\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / (r + 1))**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity of particle is %.2f c\"%(v/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of particle is 0.94 c\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.13, Page 11.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 11. # ratio of mass of particle to the rest mass of electron\n",
-      "\n",
-      "#Calculations\n",
-      "KE = (r - 1) * 9.1e-31 * 3e8**2 / (1.6e-19)\n",
-      "m = 3e8 * sqrt(1 - (1 / r)**2) * 9.1e-31 * 11\n",
-      "\n",
-      "#Result\n",
-      "print \"Kinetic energy of electron is %.1f MeV\\nMomentum of particle is %.2e N-sec\"%(KE/1e6,m)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Kinetic energy of electron is 5.1 MeV\n",
-        "Momentum of particle is 2.99e-21 N-sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.14, Page 11.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "m = 1.67e-27  # mass of electron in kg\n",
-      "m_ = 9.1e-31 # rest mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (m_ / m)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity of electron is %.3e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of electron is 3.000e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.15, Page 11.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 0.1 # kinetic speed of electron in Mev\n",
-      "\n",
-      "#Calculations\n",
-      "v_ = sqrt(2 * (E * 1.6e-13) / 9.1e-31)\n",
-      "v = 3e8 * sqrt(1 - (1 / (1 + (1.6e-13 * E) / (9.1e-31 * 3e8**2)))**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Speed according to classical mechanics is %.2e meter/sec\\nSpeed according to relativistic mechanics is %.2e meter/sec\"%(v_,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed according to classical mechanics is 1.88e+08 meter/sec\n",
-        "Speed according to relativistic mechanics is 1.64e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.17, Page 11.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r1 = 3. # ratio of kinetic energy of body to its rest mass in first case\n",
-      "r2 = 1. # ratio of kinetic energy of body to its rest mass in second case\n",
-      "\n",
-      "#Calculations\n",
-      "v1 = 3e8 * sqrt(1 - (1 / (r1 + 1))**2)\n",
-      "v2 = 3e8 * sqrt(1 - (1 / (r2 + 1))**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Velocity of particle if kinetic energy is %d times of rest mass energy  is %.2e meter/sec\\nVelocity of particle if kinetic energy is %.1e times of rest mass energy  is %e meter/sec\"%(r1,v1,r2,v2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of particle if kinetic energy is 3 times of rest mass energy  is 2.90e+08 meter/sec\n",
-        "Velocity of particle if kinetic energy is 1.0e+00 times of rest mass energy  is 2.598076e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.19, Page 11.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 1.5 # kinetic energy of electron in Mev\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / (1 + (1.6e-19 * 2e6) / (9.1e-31 * 3e8**2)))**2)\n",
-      "m = (E * 1.6e-13 / (3e8)**2) + 9.1e-31\n",
-      "\n",
-      "#Results\n",
-      "print \"Speed of electron is %.2e meter/sec\\nMass of electron is %.1e kg\"%(v,m)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of electron is 2.94e+08 meter/sec\n",
-        "Mass of electron is 3.6e-30 kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 40
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.20, Page 11.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "r = 3. / 2 # ratio of mass of metre stick to the rest mass of metre stick\n",
-      "\n",
-      "#Calculations\n",
-      "l = 1 * (1. / r)\n",
-      "\n",
-      "#Result\n",
-      "print \"Length of meter stick is %.2f meter if mass is %.2f times of its rest mass\"%(l,r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Length of meter stick is 0.67 meter if mass is 1.50 times of its rest mass\n"
-       ]
-      }
-     ],
-     "prompt_number": 43
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.21, Page 11.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "# Given \n",
-      "r = 1. / 2 # ratio of area of circular lamina in frame S_ to the ratio of area of circular lamina in frame S\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - r**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity of frame S_ w.r.t. frame S is %.1e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of frame S_ w.r.t. frame S is 2.6e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 45
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.22, Page 11.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import * \n",
-      "# Given \n",
-      "t = 1 # lose in time in an hour in minute\n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - ((60. - t) / 60)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of clock is %.2e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of clock is 5.45e+07 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 47
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.23, Page 11.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "# Given \n",
-      "t_ = 2.5e-8 # proper life of pi+ mesons in sec\n",
-      "v = 2.4e8 # velocity of beam of mesons in m/sec\n",
-      "r = 1. / exp(2) # ratio of final flux to initial flux of the meson beam\n",
-      "\n",
-      "#Calculations\n",
-      "t = t_ / sqrt(1 - (v / 3e8)**2)\n",
-      "T = t * log(1. / r)\n",
-      "d = T * v\n",
-      "\n",
-      "#Result\n",
-      "print \"Distance travel by the beam is %.2f meter\"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance travel by the beam is 20.00 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 48
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.24, Page 11.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "v = 1.8e8 # velocity of space ship away from the earth in m/sec\n",
-      "v1 = 2.1e8 # velocity of rocket w.r.t. space ship away from the earth in first case in m/sec\n",
-      "v2 = -2.1e8 # velocity of rocket w.r.t. space ship away from the earth in second case in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "u1 = (v1 + v) / (1 + ((v1 * v) / (3e8)**2))\n",
-      "u2 = (v2 + v) / (1 + ((v2 * v) / (3e8)**2))\n",
-      "\n",
-      "#Results\n",
-      "print \"Velocity of rocket w.r.t. earth in first case = %.2f c away from the earth\\nVelocity of rocket w.r.t. earth in second case = %.2f c away from the earth \"%(u1/3e8,u2/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of rocket w.r.t. earth in first case = 0.92 c away from the earth\n",
-        "Velocity of rocket w.r.t. earth in second case = -0.17 c away from the earth \n"
-       ]
-      }
-     ],
-     "prompt_number": 49
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.25, Page 11.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "l = 1 # length of the rod in meter\n",
-      "v = 1.8e8 # speed of rod along its length in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "L = l * sqrt(1- (v / 3e8)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Length as it appear to the observer is %.1f meter\"%L"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Length as it appear to the observer is 0.8 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 50
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.26, Page 11.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "l = 2 # length of the rod in meter\n",
-      "v = 2.7e8 # speed of rod along its length in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "L = l * sqrt(1- (v / 3e8)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Length as it appear to the observer is %.3f meter\"%L"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Length as it appear to the observer is 0.872 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 51
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.27, Page 11.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "l = 100. # consider the length of the rod in meter\n",
-      "v = 2.4e8 # speed of rod in meter/sec\n",
-      "theta = pi / 3 # direction of velocity of rod along its length in radian\n",
-      "\n",
-      "#Calculations\n",
-      "Lx = l * cos(theta)\n",
-      "Ly = l * sin(theta)\n",
-      "L_x = Lx * sqrt(1 - (v / 3e8)**2)\n",
-      "L_y = Ly \n",
-      "L = sqrt(L_x**2 + L_y**2)\n",
-      "p_l = ((l - L) / l) * 100 \n",
-      "\n",
-      "#Result\n",
-      "print \"Percentage length contraction is %.1f percent\"%p_l"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Percentage length contraction is 8.3 percent\n"
-       ]
-      }
-     ],
-     "prompt_number": 52
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.28, Page 11.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "# Given \n",
-      "r = 0.5 # ratio of length of rod when it is in motion to the length of the rod when it is in rest \n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - r**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of the rod relative to observer is %.3f c\"%(v/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of the rod relative to observer is 0.866 c\n"
-       ]
-      }
-     ],
-     "prompt_number": 53
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.29, Page 11.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "l = 5 # length of the rod in meter\n",
-      "v = 1.8e8 # speed of rod in meter/sec\n",
-      "theta = pi / 6 # direction of velocity of rod along its length in radian\n",
-      "\n",
-      "#Calculations\n",
-      "Lx = l * cos(theta)\n",
-      "Ly = l * sin(theta)\n",
-      "L_x = Lx * sqrt(1 - (v / 3e8)**2)\n",
-      "L_y = Ly \n",
-      "L = sqrt(L_x**2 + L_y**2)\n",
-      "orientation = atan(L_y / L_x) * (180 / pi)\n",
-      "\n",
-      "#Results\n",
-      "print \"Length of the rod in moving frame is %.2f meter\\nOrientation of the rod is %.2f degree\"%(L,orientation)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Length of the rod in moving frame is 4.27 meter\n",
-        "Orientation of the rod is 35.82 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 55
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.30, Page 11.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "T = 17.8e-9 # half-life of prticle at rest in sec\n",
-      "v = 2.4e8 # speed of particle in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "t = T / (sqrt(1 - (v / 3e8)**2))\n",
-      "\n",
-      "#Result\n",
-      "print \"New half-life of particle is %.2f nanosec\"%(t/1e-9)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "New half-life of particle is 29.67 nanosec\n"
-       ]
-      }
-     ],
-     "prompt_number": 56
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.31, Page 11.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "T = 24 # no. of hours in a day\n",
-      "v = 1e8 # speed of spaceship in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "t = T * (sqrt(1 - (v / 3e8)**2))\n",
-      "T_ = T - t\n",
-      "m=(T_-1)*60\n",
-      "s=(m-22)*60\n",
-      "\n",
-      "#Result\n",
-      "print \"Time lost per day is %d hours %d minute %d sec\"%(T_,m,s)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time lost per day is 1 hours 22 minute 21 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 58
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.32, Page 11.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "T = 4. # no. of year when rocket is moving corresponding to one year \n",
-      "\n",
-      "#Calculations\n",
-      "v = 3e8 * sqrt(1 - (1 / T)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of rocket is %.2f c\"%(v/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of rocket is 0.97 c\n"
-       ]
-      }
-     ],
-     "prompt_number": 60
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.33, Page 11.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 4 # distance of star from the earth in light years\n",
-      "v = 3e8 * sqrt(0.9999) # speed of rocket in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "t = (2 * d * 3e8) / v\n",
-      "T_ = t * sqrt(1 - (v / 3e8)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Time taken by the rocket is %.2f year\"%T_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time taken by the rocket is 0.08 year\n"
-       ]
-      }
-     ],
-     "prompt_number": 61
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.34, Page 11.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 2e-7 # life time of particle when it is moving in sec\n",
-      "v = 2.8e8 # speed of particle in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "T_ = t * sqrt(1 - (v / 3e8)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Proper life time of particle is %.2e sec\"%T_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Proper life time of particle is 7.18e-08 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 62
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.35, Page 11.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "v1 = 2.7e8 # velocity of first electron beam in meter/sec\n",
-      "v2 = -2.7e8 # velocity of second electron beam in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "u = v1 - v2\n",
-      "u_ = (v1 - v2) / (1 - (v1 * v2) / (3e8)**2)\n",
-      "\n",
-      "#Results\n",
-      "print \"Velocity of electrons beam w.r.t. another electron beam according to Newtonian mechanics is %.1f c\\nVelocity of electrons beam measured by the observer moving with other electron beam = %.2f c\"%(u/3e8,u_/3e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of electrons beam w.r.t. another electron beam according to Newtonian mechanics is 1.8 c\n",
-        "Velocity of electrons beam measured by the observer moving with other electron beam = 0.99 c\n"
-       ]
-      }
-     ],
-     "prompt_number": 63
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.37, Page 11.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E = 900 # total relativistic energy of proton in Mev\n",
-      "m = 1.63-27 # rest mass of proton in kg\n",
-      "c = 3e8 # velocity of photon in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "m_ = (E * 1.6e-13) / (c)**2\n",
-      "\n",
-      "#Results\n",
-      "print \"Relativistic mass of proton is %.2e kg\\nHere relativistic mass is same as rest mass\\n hence proton is at rest and speed and kinetic energy of proton will be zero\"%(m_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Relativistic mass of proton is 1.60e-27 kg\n",
-        "Here relativistic mass is same as rest mass\n",
-        " hence proton is at rest and speed and kinetic energy of proton will be zero\n"
-       ]
-      }
-     ],
-     "prompt_number": 64
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.38, Page 11.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E = 5.4e6 # energy liberates during dynamite explosion in J/kg\n",
-      "c = 3e8 # velocity of photon in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = 1 * c**2 # energy liberated by 1 kg content in J\n",
-      "f = E / E_\n",
-      "\n",
-      "#Result\n",
-      "print \"Fraction of total energy content in it is %.1e per kg\"%f"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fraction of total energy content in it is 6.0e-11 per kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 65
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.39, Page 11.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import * \n",
-      "# Given \n",
-      "k = 1.02 # kinetic energy of electron in Mev\n",
-      "E_ = 0.51 # rest mass energy of electron in Mev\n",
-      "c = 3e8 # velocity of photon in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "E = k + E_\n",
-      "v = c * sqrt(1 - (E_ / E)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Speed of the electron is %.2e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Speed of the electron is 2.83e+08 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 66
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11.40, Page 11.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 1400 # solar energy receives by the earth in W/square meter\n",
-      "d = 1.5e11 # distance between earth and the sun in meter\n",
-      "c = 3e8 # velocity of photon in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = 4 * pi * d**2 * E\n",
-      "m = E_ / c**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Rate of decrement of mass of the sun is %.2e kg/sec\"%m"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Rate of decrement of mass of the sun is 4.40e+09 kg/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 67
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_12.ipynb b/Engineering_Physics/Chapter_12.ipynb
deleted file mode 100755
index 1b8c5610..00000000
--- a/Engineering_Physics/Chapter_12.ipynb
+++ /dev/null
@@ -1,1613 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 12: Applied Nuclear Physics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.1, Page 12.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import log\n",
-      "\n",
-      "# Given \n",
-      "E = 1.14 # energy of gamma radiation in Mev\n",
-      "l = 0.2 # length of aluminium in meter\n",
-      "p = 0.03 # reduce in intensity in beam\n",
-      "d = 2700 # density of aluminium in kg/m^3 \n",
-      "\n",
-      "#Calculations\n",
-      "mu = (1 / l) * log(1 / p)\n",
-      "k = mu / d\n",
-      "x = 0.693 / mu\n",
-      "\n",
-      "#Result\n",
-      "print \"Mass absorption coeffiecient of Al for this radiation is %f m^2/kg\\nHalf value thickness is %.4f meter\"%(k,x)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass absorption coeffiecient of Al for this radiation is 0.006494 m^2/kg\n",
-        "Half value thickness is 0.0395 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.2, Page 12.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given that\n",
-      "E = 1.1 # energy of gamma radiation in Mev\n",
-      "l = 0.25 # length of aluminium in meter\n",
-      "p = 0.02 # reduce in intensity in beam\n",
-      "d = 2700 # density of aluminium in kg/m^3 \n",
-      "\n",
-      "#Calculations\n",
-      "mu = (1 / l) * log(1 / p)\n",
-      "k = mu / d\n",
-      "x = 0.693 / mu\n",
-      "\n",
-      "#Result\n",
-      "print \"Mass attenuation coefficient of Al for this radiation is %.1e m^2/kg\\nHalf value thickness is %.4f meter\"%(k,x)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass attenuation coefficient of Al for this radiation is 5.8e-03 m^2/kg\n",
-        "Half value thickness is 0.0443 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.3, Page 12.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 15 # half-life for Na(23) in hours\n",
-      "r = 93.75 # percentage fraction of sample which decayed \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / t\n",
-      "T = (1 / lamda) * (log(100 / (100 - r)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Time taken for 93.75 per decay of sample is %d hours\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time taken for 93.75 per decay of sample is 60 hours\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.4, Page 12.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 4 # half-life of radioactive element in years\n",
-      "r = 1. / 64 # ratio of mass of element present in specimen to the initial mass of element \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / t\n",
-      "T = (1 / lamda) * log(1 / r)\n",
-      "\n",
-      "#Result\n",
-      "print \"Time after which element present in specimen reduce to 1/64 of its original value is %d years\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time after which element present in specimen reduce to 1/64 of its original value is 24 years\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.5, Page 12.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 15 # half-life of radioactive element in years\n",
-      "r = 0.025 # ratio of mass of element present in specimen to the intial mass of element \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / t\n",
-      "T = (1 / lamda) * log(1 / r)\n",
-      "\n",
-      "#result\n",
-      "print \"Period in which 2.5 percent of the initial quantity left over is %.2f years\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Period in which 2.5 percent of the initial quantity left over is 79.85 years\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.6, Page 12.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 3.8 # half-life for radon in days\n",
-      "r = 60. # percentage fraction of sample which decayed \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / t\n",
-      "T = (1 / lamda) * (log(100 / (100 - r)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Time taken for 60 percent decay of sample is %.3f days\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time taken for 60 percent decay of sample is 5.024 days\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.7, Page 12.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 4.28e-4 # decay constant in per year\n",
-      "\n",
-      "#Calculations\n",
-      "T = 0.693 / lamda\n",
-      "t = 1 / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Half life time is %.2f years\\nMean life time is %.2f years\"%(T,t)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Half life time is 1619.16 years\n",
-        "Mean life time is 2336.45 years\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.8, Page 12.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 30 # time in years\n",
-      "r = 1. / 64 # ratio of final mass of element to the intial mass of element \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = log(1 / r) / t\n",
-      "T = 0.693 / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Half life of radioactive material is %d years\"%(ceil(T))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Half life of radioactive material is 5 years\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.9, Page 12.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "t = 2.1 # half life in minute\n",
-      "r = 60 # percentage fraction of sample which decayed \n",
-      "\n",
-      "#Calculation\n",
-      "lamda = 0.693 / t\n",
-      "\n",
-      "#Result\n",
-      "print \"Decay constant is %.2f per minute\"%lamda"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Decay constant is 0.33 per minute\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.10, Page 12.35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 2.7 # half-life of Au(198) in days\n",
-      "m = 1e-6 # mass of sample in gm\n",
-      "T = 8 * 86400 # time in seconds\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / (t * 86400)\n",
-      "N = (m * 6.023e23) / 198 # by the formula (N = mass*Avogadro number/molar mass)\n",
-      "A_ = lamda * N\n",
-      "A = A_ * (1 / exp(lamda * T))\n",
-      "\n",
-      "#Result\n",
-      "print \"Activity of sample is %.4e decays/sec\"%A"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Activity of sample is 1.1595e+09 decays/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.11, Page 12.35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 3 # no. of half lives\n",
-      "\n",
-      "#Calculation\n",
-      "f = (1. / 2)**n\n",
-      "\n",
-      "#Result\n",
-      "print \"Fraction of sample left after %d half lives is %.3f  \"%(n,f)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fraction of sample left after 3 half lives is 0.125  \n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.12, Page 12.35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "t = 2 # life period of radioactive substance in years\n",
-      "T = 4 # time in years\n",
-      "m = 10. # mass of substance in mg\n",
-      "\n",
-      "#Calculation\n",
-      "N = m / T # in mg\n",
-      "\n",
-      "#Result\n",
-      "print \"Substance remained unchanged after 4 years is %.1f mg\"%N"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Substance remained unchanged after 4 years is 2.5 mg\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.13, Page 12.36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given that\n",
-      "m = 1. # initial mass of radium in gm\n",
-      "m_ = 0.0021 # final mass of radium in gm\n",
-      "t = 5. # time for decay from m to m_ in years\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = log(m / (1 - m_)) / t\n",
-      "T = 0.693 / lamda\n",
-      "T_ = 1. / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Decay constant is %.4f per year\\nHalf life of sample is %.1f years\\nAverage life of sample is %.3f years\"%(lamda,T,T_)\n",
-      "#Incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Decay constant is 0.0004 per year\n",
-        "Half life of sample is 1648.3 years\n",
-        "Average life of sample is 2378.452 years\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.14, Page 12.36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 10. # time in days\n",
-      "r = 15. # percentage fraction of sample which remain \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = log(100. / 15) / t\n",
-      "T = 0.693 / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Half life of sample is %.3f days\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Half life of sample is 3.653 days\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.15, Page 12.36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 12.3 # half life in year\n",
-      "T = 50 # time in year \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / t\n",
-      "f = 1 / exp(lamda * T)\n",
-      "\n",
-      "#Result\n",
-      "print \"Fraction of radioactive isotope remained is %.2f \"%f"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fraction of radioactive isotope remained is 0.06 \n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.16, Page 12.37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "R = 1 # radioactivity of Pb(214) in curie\n",
-      "t = 26.8 # half life in minute \n",
-      "\n",
-      "#calculations\n",
-      "lamda = 0.693 / (t * 60)\n",
-      "R = 1 * 3.7e10 # in disintegration per sec\n",
-      "m = (R * 214) / (6.023e23 * lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Mass of Pb(214)is %.2e gm\"%m"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of Pb(214)is 3.05e-08 gm\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.17, Page 12.37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "R = 1e6 # radioactivity of Pb(214) in disintegrations per sec\n",
-      "t = 26.8 # half life in minute \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / (t * 60)\n",
-      "m = (R * 214) / (6.023e23 * lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Mass of Pb(214) is %.2e gm\"%m"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of Pb(214) is 8.24e-13 gm\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.18, Page 12.37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "m = 1. # mass of Ra(226) in gm \n",
-      "R = 1. # radioactivity of Ra(226) in curie\n",
-      "\n",
-      "#Calculations\n",
-      "r = R * 3.7e10 # in disintegrations per sec\n",
-      "N = 6.023e23 * m / 226\n",
-      "lamda = r * 226 / 6.023e23\n",
-      "T = 1. / lamda\n",
-      "T_ = 0.693 / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Mean life of radium is %.2e year\\nHalf life of radium is %.2e year\"%(T,T_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mean life of radium is 7.20e+10 year\n",
-        "Half life of radium is 4.99e+10 year\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.19, Page 12.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "m = 0.0001 # mass of Sr(90) in gm\n",
-      "t = 28. # half life of Sr(90) in year\n",
-      "t_ = 9. # time in sec\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 0.693 / (t * 86400 * 365)\n",
-      "N_ = 6.023e23 * m / 90\n",
-      "n = N_ * lamda * t_\n",
-      "\n",
-      "#Result\n",
-      "print \"Activity of Sr is %.2e disintegration/sec.\"%n\n",
-      "#Incorrect answer in the textbook\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Activity of Sr is 4.73e+09 disintegration/sec.\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.20, Page 12.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "t = 1600 # the half life of radium(226) in year\n",
-      "t1 = 3.8 # the half life of radon(222) in days\n",
-      "m = 1 # mass of Ra(226) in gm\n",
-      "\n",
-      "#Calculation\n",
-      "m_ = (222 * t1 * m) / (226 * 365 * t) # by the formula N1*t = N2*t1\n",
-      "\n",
-      "#Result\n",
-      "print \"Mass of radon is %.2e gm\"%m_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of radon is 6.39e-06 gm\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.21, Page 12.39"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "m1 = 4.002603 # mass of He(4) in a.m.u.\n",
-      "m2 = 3.016056 # mass of H(3) in a.m.u.\n",
-      "m3 = 1.007276 # mass of H(1) in a.m.u.\n",
-      "\n",
-      "#Calculations\n",
-      "k = m2 + m3 - m1\n",
-      "E = k * 931\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of gamma ray photon is %.3f MeV\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of gamma ray photon is 19.299 MeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.22, Page 12.39"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 3 # kinetic energy of proton in Mev\n",
-      "m1 = 1.007276 # mass of H(1) in a.m.u.\n",
-      "m2 = 3.016056 # mass of H(3) in a.m.u.\n",
-      "m3 = 1.008665 # mass of neutron in a.m.u.\n",
-      "m4 = 3.016036 # mass of He(3) in a.m.u.\n",
-      "\n",
-      "#calculations\n",
-      "k = m1 + m2 - m3 - m4\n",
-      "E = k * 931.5\n",
-      "\n",
-      "#Result\n",
-      "print \"Q value of reaction is %.4f MeV\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Q value of reaction is -1.2752 MeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.23, Page 12.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 200 # energy released per fission in Mev\n",
-      "m = 0.01 # mass of U(235) in gm\n",
-      "n = 235 # atomic no of sample\n",
-      "N_0=6.023e23 # Avogadro constant\n",
-      "\n",
-      "#calculations\n",
-      "E_ = E * 1.6e-13\n",
-      "k = E_ * N_0 * m / n\n",
-      "H = k / 4.168\n",
-      "\n",
-      "#Result\n",
-      "print \"Heat produce by complete disintegration is %.3e cal\\nEnergy released is %.1e J\"%(H,E_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Heat produce by complete disintegration is 1.968e+08 cal\n",
-        "Energy released is 3.2e-11 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.24, Page 12.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 200 # energy released per fission in Mev\n",
-      "m = 1 # mass of U(235) in kg\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 1.6e-13\n",
-      "k = E_ * 6.023e26 * m / 235\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy released  by fission of 1 kg of U(235)is %.2e J\"%k"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy released  by fission of 1 kg of U(235)is 8.20e+13 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.25, Page 12.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "P = 1e9 # power required for enlighten the city in watt\n",
-      "e = 30 # percentage efficiency of nuclear reactor\n",
-      "E = 3.2e-11 # energy released per fission in J\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 30 / 100\n",
-      "N = P / E_\n",
-      "N_ = N * 24 * 3600\n",
-      "m = N_ * 235 / 6.023e26 \n",
-      "\n",
-      "#Result\n",
-      "print \"Amount of fuel required per day is %.2f kg\"%m"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Amount of fuel required per day is 3.51 kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.26, Page 12.41"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 200 # energy released per fission of U(235)in Mev\n",
-      "m = 3.7 # mass of U(235) consumed in a day in kg\n",
-      "e = 20 # percentage efficiency of reactor\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 1.6e-13\n",
-      "N = m * 6.023e26 / 235\n",
-      "H = E_ * e / 100\n",
-      "k = H * N / (24 * 3600)\n",
-      "\n",
-      "#Result\n",
-      "print \"Power output of reactor is %.3f GW\"%(k * 1e-9)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Power output of reactor is 0.702 GW\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.27, Page 12.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "m1 = 4.00260 # mass of He(4) in a.m.u.\n",
-      "m2 = 0.00055 # mass of electron in a.m.u.\n",
-      "m3 = 12 # mass of C(12) in a.m.u.\n",
-      "\n",
-      "#Calculations\n",
-      "delta_m = 3 * m1 - m3\n",
-      "E = delta_m * 931\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy produce by each reaction is %.4f MeV\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy produce by each reaction is 7.2618 MeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.28, Page 12.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "P = 5e7 # power in watt\n",
-      "e = 33. # percentage efficiency of nuclear reactor\n",
-      "m1 = 2.01478 # mass of H(2) in a.m.u.\n",
-      "m2 = 4.00388 # mass of He(4) in a.m.u.\n",
-      "\n",
-      "#calculations\n",
-      "m = (2 * m1) - m2\n",
-      "E = m * 931 * 1.6e-13\n",
-      "E_O = (E * e) /(2 * 100)\n",
-      "N = P / E_O\n",
-      "k = N * m1 / 6.023e26\n",
-      "M = k * 24 * 3600 \n",
-      "\n",
-      "#Result\n",
-      "print \"Mass of deuterium consumed per day is %.4f kg\"%M"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Mass of deuterium consumed per day is 0.0229 kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.29, Page 12.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given\n",
-      "d = 1.8 # diameter in meter\n",
-      "B = 0.8 # magnetic field in tesla\n",
-      "m = 6.68e-27 # mass of He(4) in kg\n",
-      "e = 1.6e-19 # charge on an electron in Coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "r = d / 2\n",
-      "E = (B**2 * (2 * e)**2 * r**2) / (2 * m * 1.6e-19 * 10**6) \n",
-      "f = B * 2 * e / (2 * pi * m)\n",
-      "N = f / 2\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy  is %.2f MeV\\nNumber of revolution made by particle to obtain above energy is %.2e per sec\"%(E,N)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy  is 24.83 MeV\n",
-        "Number of revolution made by particle to obtain above energy is 3.05e+06 per sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.30, Page 12.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given\n",
-      "f = 12e6 # oscillator frequency of cyclotron in Hz\n",
-      "r = 0.53 # radius of dee in meter\n",
-      "e = 1.6e-19 # charge on an electron in Coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "B = (2 * pi * f * 2 * 1.67e-27) / e\n",
-      "\n",
-      "#Result\n",
-      "print \"Value of magnetic induction needed to accelerate deuteron in it is %.3f T\"%B"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Value of magnetic induction needed to accelerate deuteron in it is 1.574 T\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.31, Page 12.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "f = 10e6 # frequency of applied Emf in Hz\n",
-      "r = 0.32 # radius in meter\n",
-      "m = 3.32e-27 # mass of deuteron in kg\n",
-      "e = 1.6e-19 # charge on an electron in Coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "B = (2 * pi * f * m) / e\n",
-      "v = (e * B * r) / m\n",
-      "\n",
-      "#Result\n",
-      "print \"Flux density of the magnetic field is %.3f T\\nVelocity of the deuterons emerging out of the cyclotron is %.2e m/sec \"%(B, v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Flux density of the magnetic field is 1.304 T\n",
-        "Velocity of the deuterons emerging out of the cyclotron is 2.01e+07 m/sec \n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.32, Page 12.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "f = 60 # operating frequency in Hz\n",
-      "d = 1.6 # diameter in meter\n",
-      "B = 0.5 # magnetic field at the orbit in tesla\n",
-      "e = 1.6e-19 # charge on an electron in Coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "r = d / 2\n",
-      "w = 2 * pi * f\n",
-      "E = 4 * e * w * r**2 * B\n",
-      "E_ = 3e8 * r * B / 1e6\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy gained per turn is %.1f eV\\nFinal energy is %d MeV\"%(E / e,E_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy gained per turn is 482.5 eV\n",
-        "Final energy is 120 MeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.33, Page 12.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 70 # energy of betatron synchrotron in Mev\n",
-      "r = 0.28 # radius in meter\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 1.6e-13\n",
-      "B = E_ / (3e8 * e * r)\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnitude of magnetic field is %.2f T\"%B"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnitude of magnetic field is 0.83 T\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.34, Page 12.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 4.18 # energy of alpha particle in Mev\n",
-      "n = 12 # no. of particle enter the chamber per sec\n",
-      "E_ = 40 # required energy of an ion pair in ev\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "R = n * E * 10**6 # in eV\n",
-      "N = R / E_\n",
-      "i = N * e\n",
-      "\n",
-      "#Result\n",
-      "print \"The current produced = %.e Amp\"%i"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The current produced = 2e-13 Amp\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.35, Page 12.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given\n",
-      "n = 10**8 # no. of electron per discharge counted by GM counter\n",
-      "r = 500. # counting rate in counts per minutes\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "N = r / 60\n",
-      "i = N * n * e \n",
-      "\n",
-      "#Result\n",
-      "print \"Average current in the circuit = %.2e Amp\"%i"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average current in the circuit = 1.33e-10 Amp\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.36, Page 12.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 10 # energy of electron in kev\n",
-      "B = 5e-5 # magnetic field of earth in tesla\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "f = e * B / 9.1e-31\n",
-      "E_ = E * 1.6e-16\n",
-      "v = sqrt((2 * E_) / 9.1e-31)\n",
-      "r = v / f\n",
-      "\n",
-      "#Result\n",
-      "print \"Frequency of cyclotron = %.3e per sec\\nLarmour radius = %.3f meter\"%(f,r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency of cyclotron = 8.791e+06 per sec\n",
-        "Larmour radius = 6.745 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.37, Page 12.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "B = 5e-9 # magnetic field in tesla\n",
-      "v = 3e5 # velocity of proton stream in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#calculations\n",
-      "r = (1.67e-27 * v) / (e * B)\n",
-      "\n",
-      "#Result\n",
-      "print \"Larmour radius is %.2e meter\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Larmour radius is 6.26e+05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.38, Page 12.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 1. # energy of He+ in kev\n",
-      "r = 0.188 # Larmour radius in meter\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 1.6e-16\n",
-      "v = sqrt((2 * E_) / (4 * 1.67e-27))\n",
-      "B = (4 * 1.67e-27 * v) / (e * r)\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnetic field is %.3e tesla\"%B"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetic field is 4.861e-02 tesla\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.39, Page 12.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 3.5 # energy of He++ ash particle in Mev\n",
-      "B = 8 # magnetic field in tesla\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 1.6e-13\n",
-      "v = sqrt(2 * E_ / (4 * 1.67e-27))\n",
-      "r = (4 * 1.67e-27 * v) / (2 * e * B)\n",
-      "\n",
-      "#Result\n",
-      "print \"Larmour radius is %.2e meter\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Larmour radius is 3.38e-02 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.40, Page 12.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 1e12 # electron density in number per m^3\n",
-      "E = 0.1 # thermal energy in eV\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = sqrt((8.85e-12 * E * e) / (d * e * e))\n",
-      "omega = sqrt(d * e**2 / (9.1e-31 * 8.85e-12))\n",
-      "f = omega / (2 * pi)\n",
-      "\n",
-      "#Results\n",
-      "print \"Debye length is %.2e meter\\nPlasma frequency is %.2f MHz\"%(lamda,f / 1e6)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Debye length is 2.35e-03 meter\n",
-        "Plasma frequency is 8.97 MHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12.41, Page 12.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 1e16 # density in per m^3\n",
-      "E = 2 # thermal energy in eV\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = sqrt((8.85e-12 * E * e) / (d * e * e))\n",
-      "omega = sqrt(d * e**2 / (9.1e-31 * 8.85e-12))\n",
-      "f = omega / (2 * pi)\n",
-      "\n",
-      "#Result\n",
-      "print \"Debye length is %.4e meter\\nPlasma frequency is %.3e Hz\"%(lamda,f)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Debye length is 1.0518e-04 meter\n",
-        "Plasma frequency is 8.973e+08 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_13.ipynb b/Engineering_Physics/Chapter_13.ipynb
deleted file mode 100755
index db97b36d..00000000
--- a/Engineering_Physics/Chapter_13.ipynb
+++ /dev/null
@@ -1,995 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 13: Crystal Structure\n"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.1, Page 13.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "x = 2 # intercepts cut by the plane along vector a of crystallographic axes\n",
-      "y = 3 # intercepts cut by the plane along vector b of crystallographic axes\n",
-      "z = 1 # intercepts cut by the plane along vector c of crystallographic axes\n",
-      "\n",
-      "#Calculations\n",
-      "x_ = 6 / x\n",
-      "y_ = 6 / y\n",
-      "z_ = 6 / z\n",
-      "\n",
-      "#Result\n",
-      "print \"Miller indices of the plane are (%d %d %d)\"%(x_,y_,z_)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Miller indices of the plane are (3 2 6)\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.2, Page 13.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "x = 1 # intercepts cut by the plane along vector a of crystallographic axes\n",
-      "y = 2 # intercepts cut by the plane along vector b of crystallographic axes\n",
-      "z = -3. / 2 # intercepts cut by the plane along vector c of crystallographic axes\n",
-      "\n",
-      "#Calculations\n",
-      "x_ = 6 / x\n",
-      "y_ = 6 / y\n",
-      "z_ = 6 / z\n",
-      "\n",
-      "print \"Miller indices of the plane are (%d %d %d)\"%(x_,y_,z_)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Miller indices of the plane are (6 3 -4)\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.3, Page 13.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "x1 = 3. # intercepts cut by the plane along vector a of crystallographic axes in first case\n",
-      "y1 = 3. # intercepts cut by the plane along vector b of crystallographic axes in first case \n",
-      "z1 = 2. # intercepts cut by the plane along vector c of crystallographic axes in first case\n",
-      "x2 = 1. # intercepts cut by the plane along vector a of crystallographic axes in second case\n",
-      "y2 = 2. # intercepts cut by the plane along vector b of crystallographic axes in second case\n",
-      "k2 = 0. # raciprocal of intercepts cut by the plane along vector c of crystallographic axes in second case\n",
-      "x3 = 1. # intercepts cut by the plane along vector a of crystallographic axes in third case\n",
-      "y3 = 1./2 # intercepts cut by the plane along vector b of crystallographic axes in third case\n",
-      "z3 = 1. # intercepts cut by the plane along vector c of crystallographic axes in third case\n",
-      "\n",
-      "#Calculations\n",
-      "x_1 = 6. / x1\n",
-      "y_1 = 6. / y1\n",
-      "z_1 = 6. / z1\n",
-      "x_2 = 2. / x2\n",
-      "y_2 = 2. / y2\n",
-      "z_2 = 2*k2\n",
-      "x_3 = 2 * x3\n",
-      "y_3 = 2 * y3\n",
-      "z_3 = 2 * z3\n",
-      "\n",
-      "#Result\n",
-      "print \"Miller indices of the plane (i) In first case are (%d %d %d)\\n(ii) In second case are (%d %d %d)\\n(iii)In the third case  are (%d %d %d).\"%(x_1,y_1,z_1,x_2,y_2,z_2,x_3,y_3,z_3)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Miller indices of the plane (i) In first case are (2 2 3)\n",
-        "(ii) In second case are (2 1 0)\n",
-        "(iii)In the third case  are (2 1 2).\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.4, Page 13.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "x1 = 1 # coordinate on x axis for first plane\n",
-      "y1 = 0 # coordinate on y axis for first plane\n",
-      "z1 = 0 # coordinate on z axis for first plane\n",
-      "x2 = 1 # coordinate on x axis for second plane\n",
-      "y2 = 1 # coordinate on y axis for second plane\n",
-      "z2 = 1 # coordinate on z axis for second plane\n",
-      "\n",
-      "#Calculations\n",
-      "d1 = 1 / sqrt(x1**2 + y1**2 + z1**2)\n",
-      "d2 = 1 / sqrt(x2**2 + y2**2 + z2**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Spacing between the plane in first case is a / %d\\nSpacing between the plane in second case is a / %f\"%(d1,d2)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Spacing between the plane in first case is a / 1\n",
-        "Spacing between the plane in second case is a / 0.577350\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.5, Page 13.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given that\n",
-      "x = 1. # intercepts cut by the plane along vector a of crystallographic axes\n",
-      "y = 2. # intercepts cut by the plane along vector b of crystallographic axes\n",
-      "k = 0. # raciprocal of intercepts cut by the plane along vector c of crystallographic axes\n",
-      "a = 5. # length of vector a of crystallographic axes in angstrom\n",
-      "b = 5. # length of vector b of crystallographic axes in angstrom \n",
-      "c = 5. # length of vector c of crystallographic axes in angstrom\n",
-      "\n",
-      "#Calculations\n",
-      "x_ = 2. / x\n",
-      "y_ = 2. / y\n",
-      "z_ = 2 * k\n",
-      "d = a / sqrt(x_**2 + y_**2 + z_**2)\n",
-      "D=d**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Miller indices of the plane are (%d %d %d)\\nInter planar distance is sqrt(%d) angstrom\"%(x_,y_,z_,D)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Miller indices of the plane are (2 1 0)\n",
-        "Inter planar distance is sqrt(0) angstrom\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.6, Page 13.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "x = 2 # intercepts cut by the plane along vector a of crystallographic axes\n",
-      "y = 2. / 3 # intercepts cut by the plane along vector b of crystallographic axes\n",
-      "k = 0 # raciprocal of intercepts cut by the plane along vector c of crystallographic axes\n",
-      "\n",
-      "#Calculations\n",
-      "x_ = 2. / x\n",
-      "y_ = 2. / y\n",
-      "z_ = 2 * k\n",
-      "\n",
-      "#Result\n",
-      "print \"Miller indices of the plane are (%d %d %d)\"%(x_,y_,z_)\n",
-      "\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Miller indices of the plane are (1 3 0)\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.7, Page 13.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "x1 = 2 # coordinate on x axis \n",
-      "y1 = 3 # coordinate on y axis \n",
-      "z1 = 1 # coordinate on z axis \n",
-      "r = 0.175 # atomic radius of fcc structure in nm\n",
-      "\n",
-      "#Calculations\n",
-      "a = (4 * r) / sqrt(2)\n",
-      "d = a / sqrt(x1**2 + y1**2 + z1**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Inter planar spacing is %.3f nm\"%d\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Inter planar spacing is 0.132 nm\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.8, Page 13.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "x1 = 1 # coordinate on x axis in first case\n",
-      "y1 = 2 # coordinate on y axis in first case \n",
-      "z1 = 3 # coordinate on z axis in first case\n",
-      "x2 = 1\n",
-      "y2 = 1\n",
-      "z2 = 0\n",
-      "# coordinate of first plane in second case\n",
-      "x3 = 1\n",
-      "y3= 1\n",
-      "z3 = 1\n",
-      "# coordinate of second plane in second case\n",
-      "\n",
-      "#Calculations\n",
-      "x_=6/x1\n",
-      "y_=6/y1\n",
-      "z_=6/z1\n",
-      "d1 = 1 / sqrt(x2^2 + y2^2 + z2^2)\n",
-      "d2= 1/ sqrt(x3^2 + y3^2 + z3^2)\n",
-      "d = d1/d2\n",
-      "\n",
-      "#Results\n",
-      "print \"The ratio of intercepts of three axes by the point are %d : %d : %d\\nThe ratio of spacing between two planes is %.3f\"%(x_,y_,z_,d)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The ratio of intercepts of three axes by the point are 6 : 3 : 2\n",
-        "The ratio of spacing between two planes is 1.225\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.9, Page 13.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "a = 5 # the lattice constant of the structure in angstrom\n",
-      "\n",
-      "#Calculations\n",
-      "d = (sqrt(3) / 4) * a\n",
-      "\n",
-      "#Result\n",
-      "print \"Distance between two atoms is %.2f A\"%d\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance between two atoms is 2.17 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.10, Page 13.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given that\n",
-      "a = 3.56 # the length of cube edge in angstrom\n",
-      "\n",
-      "#Calculations\n",
-      "d = a / sqrt(2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Permitive translation vector is %.2f A\"%d\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Permitive translation vector is 2.52 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.11, Page 13.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "w = 207.2 # atomic weight of Pb\n",
-      "d = 11.36e3 # density of Pb in kg/m^3\n",
-      "a = 3.2e-10 # length of cube edge in meter\n",
-      "N = 6.023e26 # Avogadro's no. in per kg mole\n",
-      "\n",
-      "#Calculations\n",
-      "n = (a**3 * d * N) / w\n",
-      "\n",
-      "#Result\n",
-      "print \"Number  of atom per unit cell is %d\"%n\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number  of atom per unit cell is 1\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.12, Page 13.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "M = 60.2 # molecular weight\n",
-      "d = 6250 # density in kg/m^3\n",
-      "N = 6.023e+26 # Avogadro's no. in per kg mole\n",
-      "n = 4. # for fcc lattice\n",
-      "\n",
-      "#Calculations\n",
-      "a = (((4 * M) / (N * d))**(1. / 3)) * 1e10\n",
-      "\n",
-      "#Result\n",
-      "print \"Lattice constant is %.f A\"%a\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Lattice constant is 4 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.13, Page 1329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "x1 = 1 # coordinate on x axis of plane\n",
-      "y1 = 0 # coordinate on y axis of plane\n",
-      "z1 = 0 # coordinate on z axis of plane\n",
-      "d = 2.82 # the space between successive plane in angstrom\n",
-      "theta = 8.8 # glancing angle in degree\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1\n",
-      "lamda = 2 * d * sin(theta*pi/180) / n\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of x-ray is %.3f A\"%lamda\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of x-ray is 0.863 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.14, Page 13.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 2.51 # the space between adjacent plane in angstrom\n",
-      "theta = 9 # glancing angle in degree\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "lamda = 2 * d * sin(theta*pi/180) / n\n",
-      "n = 2 # for n=2\n",
-      "theta = degrees(asin(lamda / d))\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of x-ray is %.4f A\\nGlancing angle for second order diffraction is %.1f degree\"%(lamda,theta)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of x-ray is 0.7853 A\n",
-        "Glancing angle for second order diffraction is 18.2 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.15, Page 13.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 1.5 # wavelength of x-ray in angstrom\n",
-      "theta = 60 # glancing angle in degree\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for first order\n",
-      "d = ( n * lamda) / (2 * sin(theta*pi/180))\n",
-      "\n",
-      "#Result\n",
-      "print \"Lattice constant of NaCl is %.2f A\"%d\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Lattice constant of NaCl is 0.87 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.16, Page "
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 1.4 # wavelength of x-ray in angstrom\n",
-      "x1 = 1 # coordinate on x axis of plane\n",
-      "y1 = 1 # coordinate on y axis of plane\n",
-      "z1 = 1 # coordinate on z axis of plane\n",
-      "a = 5. # lattice parameter of of crystal in angstrom\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for first order\n",
-      "d = a / sqrt(x1**2 + y1**2 + z1**2)\n",
-      "theta = degrees(asin((n * lamda) / (2 * d)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle of incidence of x-ray on the plane is %.f degree\"%theta\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of incidence of x-ray on the plane is 14 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.17, Page 13.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 0.710 # wavelength of x-ray in angstrom\n",
-      "x1 = 1 # coordinate on x axis of plane\n",
-      "y1 = 0 # coordinate on y axis of plane\n",
-      "z1 = 0 # coordinate on z axis of plane\n",
-      "a = 2.814 # lattice parameter of of crystal in angstrom\n",
-      "\n",
-      "#Calculations\n",
-      "n = 2 # for second order\n",
-      "d = a / sqrt(x1**2 + y1**2 + z1**2)\n",
-      "theta = degrees(asin((n * lamda) / (2 * d)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Glancing angle is %.1f degree\"%theta\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Glancing angle is 14.6 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.18, Page 13.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "n = 1 # order of brag reflection \n",
-      "d = 3.84e-10 # the space between successive plane in m\n",
-      "theta = 30. # glancing angle in degree\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 2 * d * sin(theta*pi/180) / n\n",
-      "v = 6.62e-34 / (1.67e-27 * lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of neutron beam is %.2f A\\nSpeed of neutron beam is %.2e meter/sec\"%(lamda * 10**10,v)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of neutron beam is 3.84 A\n",
-        "Speed of neutron beam is 1.03e+03 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.19, Page 13.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 120 # voltage at which electron is accelerated in v\n",
-      "n = 1 # order of Bragg reflection \n",
-      "x1 = 1 # coordinate on x axis of plane\n",
-      "y1 = 1 # coordinate on y axis of plane\n",
-      "z1 = 1 # coordinate on z axis of plane\n",
-      "theta = 22 # angle at which maximum reflection is obtain in degree\n",
-      "n = 1 # order of reflection\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 6.62e-34 / sqrt(2 * 9.1e-31 * 1.6e-19 * v)\n",
-      "d = (n * lamda) / (2 * sin(theta*pi/180))\n",
-      "a = d * sqrt(3) \n",
-      "\n",
-      "#Result\n",
-      "print \"Lattice parameter is %.3f A\"%(a * 10**10)                           "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Lattice parameter is 2.589 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.20, Page 13.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 1.24e-10 # wavelength of X-ray in A\n",
-      "x1 = 1 # coordinate on x axis of first plane\n",
-      "y1 = 0 # coordinate on y axis of first plane\n",
-      "z1 = 0 # coordinate on z axis of first plane\n",
-      "x2 = 1 # coordinate on x axis of second plane\n",
-      "y2 = 1 # coordinate on y axis of second plane\n",
-      "z2 = 0 # coordinate on z axis of second plane\n",
-      "x3 = 1 # coordinate on x axis of third plane\n",
-      "y3 = 1 # coordinate on y axis of third plane\n",
-      "z3 = 1 # coordinate on z axis of third plane\n",
-      "M = 74.5 # molecular weight of KCl\n",
-      "d = 1980 # density of KCl in kg/m^3\n",
-      "N = 6.023e+26 # Avogadro's No per Kg mole\n",
-      "\n",
-      "#Calculations\n",
-      "a = (4*M / (N*d))**(1./3)\n",
-      "D1 = a/sqrt(x1**2 + y1**2 + z1**2)\n",
-      "D2 = a/sqrt(x2**2 + y2**2 + z2**2)\n",
-      "D3 = a/sqrt(x3**2 + y3**2 + z3**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Inter planner distances are - \\n(1) in first case %.1f A \\n(2) in second case %.2f A \\n(3) in third case %.2f A\"%(D1*10**10,D2*10**10,D3*10**10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Inter planner distances are - \n",
-        "(1) in first case 6.3 A \n",
-        "(2) in second case 4.45 A \n",
-        "(3) in third case 3.64 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 35
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.21, Page 13.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 0.15e-9 # distance between K(+) and Cl(-) in m\n",
-      "\n",
-      "#Calculations\n",
-      "v = -1.6e-19 / (4 * pi * 8.85e-12 * d)\n",
-      "\n",
-      "#Result\n",
-      "print \"Potential energy of molecule is %.1f eV\"%v\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Potential energy of molecule is -9.6 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.22, Page 13.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 0.32e-9 # equilibrium separation in m\n",
-      "alpha = 1.748 \n",
-      "n = 9\n",
-      "e = 4 # ionization energy in eV\n",
-      "a = -2.16 # electron affinity in eV\n",
-      "\n",
-      "#Calculations\n",
-      "E = -((alpha * 1.6e-19) / (4 * pi * 8.85e-12 * d)) * (1 - (1. / n))\n",
-      "\n",
-      "#Result\n",
-      "print \"Cohesive energy of Nacl is %f eV\"%E\n",
-      "#Incorrect answer in the textbook                            "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Cohesive energy of Nacl is -6.985633 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13.23, Page 13.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 2.02 # average energy required to produce a Schottky defect at room temperature in eV\n",
-      "k = 1.38e-23 # Boltzmann constant in J/k\n",
-      "T = 300 # room temperature in K\n",
-      "\n",
-      "#Calculations\n",
-      "r = exp(-(E * 1.6e-19) / (2 * k * T))\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of number of Schottky defects to total number of cation-anion pairs is %.2e\"%r\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of number of Schottky defects to total number of cation-anion pairs is 1.12e-17\n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_14.ipynb b/Engineering_Physics/Chapter_14.ipynb
deleted file mode 100755
index 498814f0..00000000
--- a/Engineering_Physics/Chapter_14.ipynb
+++ /dev/null
@@ -1,1951 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 14: Development of Quantum Mechanics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.1, Page 14.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 75 # energy of photon in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in J \n",
-      "\n",
-      "#Calculations\n",
-      "f = E * e / h\n",
-      "lamda = c / f\n",
-      " \n",
-      "#Result\n",
-      "print \"Frequency is %.2e Hz\\nWavelength is %.1f A\"%(f,lamda * 10**10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency is 1.81e+16 Hz\n",
-        "Wavelength is 165.5 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.2, Page 14.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "P = 2e5 # radiated power in W\n",
-      "f = 98e6 # frequency in Hz \n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "\n",
-      "#Calculations\n",
-      "E = h * f\n",
-      "n = P / E\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of quanta emitted per sec is %.2e\"%n\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of quanta emitted per sec is 3.08e+30\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.3, Page 14.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 4e-7 # wavelength of spectral line in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "\n",
-      "#Calculations\n",
-      "E = (h * c) / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of photon is %.3e J\"%E\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of photon is 4.965e-19 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.4, Page 14.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "lamda = 5e-7 # wavelength of green light in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "P = 1. # energy in erg\n",
-      "\n",
-      "#Calculations\n",
-      "E = ((h * c) / lamda) * (10**7)\n",
-      "n = P / E\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of photons of green light emitted is %.2e\"%n\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of photons of green light emitted is 2.52e+11\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.5, Page 14.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "E = 5e-19 # energy of photon in J\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = (c * h) / E\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength is %.f A\"%(lamda * 10**10)\n",
-      "#Incorrect answer in the textbook                    "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength is 3972 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.6, Page 14.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 4.35e-7 # wavelength of green light in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "P = 1 # energy in erg\n",
-      "\n",
-      "#Calculations\n",
-      "E = ((h * c) / lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of an electron is %.3e J\"%E\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of an electron is 4.566e-19 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.7, Page 14.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 5.6e-7 # wavelength of light in meter\n",
-      "n = 120 # no. of photons per second\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "\n",
-      "#Calculations\n",
-      "E = ((h * c) / lamda)\n",
-      "p = E * n\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy received by the eye per second is %.3e W\"%p\n",
-      "#Incorrect answer in the textbook                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy received by the eye per second is 4.256e-17 W\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.8, Page 14.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 5.5e-7 # wavelength of light in meter\n",
-      "E = 1.5 # energy in J\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "\n",
-      "#Calculations\n",
-      "E_ = ((h * c) / lamda)\n",
-      "n = E / E_\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of photons of yellow light = %.3e\"%n\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of photons of yellow light = 4.154e+18\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.9, Page 14.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 4.35e-7 # wavelength of light in meter\n",
-      "lambda_ = 5.42e-7 # threshold wavelength of photoelectron in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "w = ((h * c) / lambda_)\n",
-      "v = sqrt(((2 * h * c) / m) * (1 / lamda - 1 / lambda_))\n",
-      "V = m * v**2 / (2 * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Work function is %.3e J\\nStopping potential is %.2f V\\nMaximum velocity is %.3e m/sec\"%(w,V,v)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Work function is 3.664e-19 J\n",
-        "Stopping potential is 0.56 V\n",
-        "Maximum velocity is 4.451e+05 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.10, Page 14.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "f = 1.2e15 # frequency of light in Hz\n",
-      "f_ = 1.1e+15 # threshold frequency of photoelectron emission in copper in Hz\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E = h * (f - f_) / e\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum energy of photoelectron is %.3f eV\"%E\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum energy of photoelectron is 0.414 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.11, Page 14.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 6.2e-7 # threshold wavelength of photoelectron in first case in meter\n",
-      "lambda_ = 5e-7 # threshold wavelength of photoelectron in second case in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "w = ((h * c) / lamda) * (1 / e)\n",
-      "w_ = ((h * c) / lambda_) * (1 / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Work function for wavelength %.e A is %.f eV\\nWork function for wavelength %.e A is %.2f eV\"%(lamda,w,lambda_,w_)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Work function for wavelength 6e-07 A is 2 eV\n",
-        "Work function for wavelength 5e-07 A is 2.48 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.12, Page 14.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "lamda = 3.132e-7 # wavelength of light in meter\n",
-      "V = 1.98 # stopping potential in V\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "E = e * V\n",
-      "lambda_ = 1. / ((1. / lamda) - (E / (h * c)))\n",
-      "f = c / lambda_\n",
-      "w = ((h * c) / lambda_)\n",
-      "\n",
-      "#Result\n",
-      "print \"Work function is %.3e J\\nMaximum energy is %.3e J\\nThreshold frequency is %.3e Hz\"%(w,E,f)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Work function is 3.173e-19 J\n",
-        "Maximum energy is 3.168e-19 J\n",
-        "Threshold frequency is 4.793e+14 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.13, Page 14.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "w = 4.8 # work function in eV\n",
-      "lambda1 = 5e-7 # wavelength of incident radiation in first case in meter\n",
-      "lambda2 = 2e-7 # wavelength of incident radiation in second case in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E_k1 = h*c/lambda1\n",
-      "E_k2 = h*c / lambda2\n",
-      "\n",
-      "#Result\n",
-      "print \"The energy corresponding to wavelength 5000 A is %.2f which is found to be less than the work function 4.8 eV\"%(E_k1/e) \n",
-      "print \"The energy corresponding to wavelength 2000 A %.2f is found to be greater than the work function\"%(E_k2/e)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The energy corresponding to wavelength 5000 A is 2.48 which is found to be less than the work function 4.8 eV\n",
-        "The energy corresponding to wavelength 2000 A 6.21 is found to be greater than the work function\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.14, Page 14.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 5.893e-7 # wavelength of light in meter\n",
-      "V = 0.36 # stopping potential for emitted electron in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "E = h * c / lamda\n",
-      "w = ((h * c) / lamda) * (1 / e) - V\n",
-      "f = w * e / h\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum energy is %.2f eV\\nWork function is %.2f eV\\nThreshold frequency is %.2e cycles/sec\"%(E/e,w,f)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum energy is 2.11 eV\n",
-        "Work function is 1.75 eV\n",
-        "Threshold frequency is 4.22e+14 cycles/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.15, Page 14.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "lamda = 5.89e-7 # wavelength of light in meter\n",
-      "lambda_ = 7.32e-7 # threshold wavelength of photoelectron in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "E = (h * c) * (1 / lamda - 1 / lambda_)\n",
-      "V = E / e\n",
-      "\n",
-      "#Result\n",
-      "print \"Stopping potential is %.3f V\\nMaximum kinetic energy is %.3e J\"%(V,E)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Stopping potential is 0.412 V\n",
-        "Maximum kinetic energy is 6.587e-20 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.16, Page 14.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E = 1.5 # maximum energy in eV\n",
-      "lambda_ = 2.3e-7 # threshold wavelength of photoelectron in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 1 / ((E * e / (h * c)) + (1 / lambda_))\n",
-      "\n",
-      "#Resuult\n",
-      "print \"Wavelength of light is %.1f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light is 1799.8 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.17, Page 14.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 1.5e-7 # wavelength of light in in meter\n",
-      "w = 4.53 # work function of tungsten in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "E = ((h * c) / lamda) * (1 / e)\n",
-      "k = E - w\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of incident photon is %.2f eV,which is greater than the work function \\nSo it causes photoelectric emission.\\nKinetic energy of the emitted electron is %.2f eV\"%(E,k)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of incident photon is 8.28 eV,which is greater than the work function \n",
-        "So it causes photoelectric emission.\n",
-        "Kinetic energy of the emitted electron is 3.75 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.18, Page 14.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "w = 2.3 # work function of sodium in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = ((h * c) / w) * (1 / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Longest wavelength required for photoemission is %.2f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Longest wavelength required for photoemission is 5396.74 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.19, Page 14.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "w = 2 # work function of sodium in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = ((h * c) / w) * (1 / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Threshold wavelength for photo emission is %d A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Threshold wavelength for photo emission is 6206 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 27
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.20, Page 14.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "k = 4 # maximum kinetic energy of electron in eV\n",
-      "w = 2.2 # work function of sodium in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "lambda_ = ((h * c) / (w * e)) \n",
-      "lamda = (1 / ((((k * e)  / (h * c))) + (1 / lambda_)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Threshold wavelength is %d A\\nIncident electromagnetic wavelength is %.f A\"%(lambda_ * 1e10,lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Threshold wavelength is 5642 A\n",
-        "Incident electromagnetic wavelength is 2002 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 35
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.21, Page 14.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 3.5e-7 # wavelength of light in meter\n",
-      "i = 1 # intensity in W/m^2\n",
-      "p = 0.5 # percent of incident photon produce electron\n",
-      "a = 1 # surface area of potassium in cm^2\n",
-      "w = 2.1 # work function of potassium in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of an electron in kg \n",
-      "\n",
-      "#Calculations\n",
-      "E = (((h * c) / lamda) * (1 / e) - w) * e\n",
-      "E_ = (p * a * 1e-4) / 100 # in W/cm^2\n",
-      "n = E_ / E\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum kinetic energy is %.3e J\\nNumber of electrons emitted per sec from 1cm^2 area is %.2e\"%(E,n)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum kinetic energy is 2.314e-19 J\n",
-        "Number of electrons emitted per sec from 1cm^2 area is 2.16e+12\n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.22, Page 14.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 5.896e-7 # wavelength of first light in meter\n",
-      "lambda_ = 2.83e-7 # wavelength of second light in meter\n",
-      "V1 = 0.12 # stopping potential for emitted electrons for first light in V\n",
-      "V2 = 2.2 # stopping potential for emitted electrons for second light in V\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "\n",
-      "#Calculations\n",
-      "h = (e * (V2 - V1) / c) / (1 / lambda_ - 1 / lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Value of Planck constant is %.2e J-sec\"%h\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Value of Planck constant is 6.04e-34 J-sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.23, Page 14.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 1e-10 # wavelength of light in meter\n",
-      "theta = 90 # angle at which scattered radiation is viewed in degree\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "delta_lambda = (h * (1 - cos(theta*pi/180))) / (m * c)\n",
-      "\n",
-      "#Result\n",
-      "print \"Compton shift is %.3f A\"%(delta_lambda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Compton shift is 0.024 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.24, Page 14.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import * \n",
-      "# Given \n",
-      "lamda = 1e-10 # wavelength of light in meter\n",
-      "theta = 90 # angle in degree\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "delta_lambda = (h * (1 - cos(theta*pi/180))) / (m * c)\n",
-      "E = (h * c) / delta_lambda\n",
-      "\n",
-      "#Result\n",
-      "print \"Compton shift is %.3f A\\nEnergy of incident beam is %.3f MeV\"%(delta_lambda * 1e10,E / 1.6e-13)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Compton shift is 0.024 A\n",
-        "Energy of incident beam is 0.512 MeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.25, Page 14.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "    \n",
-      "# Given \n",
-      "E = 4 # enrgy of recoil electron in KeV\n",
-      "theta = 180 # scattered angle of photon in degree\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "p = sqrt(2 * E * 10**3 * e * m)\n",
-      "lamda = (2 * h * c) / (p * c + E * 10**3 * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of incident beam is %.3f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of incident beam is 0.365 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.26, Page 14.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 1e-10 # wavelength of light in meter\n",
-      "theta = 90 # angle in degree\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "delta_lambda = (h * (1 - cos(theta*pi/180))) / (m * c)\n",
-      "E = (h * c) * ((1 / lamda) - (1 / (lamda + delta_lambda)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Compton shift is %.3e m\\nKinetic energy is %.f eV\"%(delta_lambda,E / 1.6e-19)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Compton shift is 2.425e-12 m\n",
-        "Kinetic energy is 294 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.27, Page 14.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 0.144e-10 # wavelength of x-ray in meter\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "theta = 180 # for maximum shift\n",
-      "d_lamda = (h * (1 - cos(theta*pi/180))) / (m * c)\n",
-      "E = (h * c) * ((1. / lamda) - (1. / (d_lamda+lamda)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum Compton shift is %.4f A\\nKinetic energy is %.2f KeV\"%(delta_lambda * 1e10,E / 1.6e-16)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum Compton shift is 0.0485 A\n",
-        "Kinetic energy is 21.72 KeV\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.28, Page 14.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "lamda = 0.2e-10 # wavelength of x-ray in meter\n",
-      "theta = 45 # scattered angle in degree\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "delta_lambda = (h * (1 - cos(theta*pi/180))) / (m * c)\n",
-      "E = (h * c) * ((1 / lamda) - (1 / (lamda + delta_lambda)))\n",
-      "theta_ = 180 # for maximum\n",
-      "delta_lambda_ = (h * (1 - cos(theta_*pi/180))) / (m * c)\n",
-      "lambda_ = lamda + delta_lambda_\n",
-      "E_k = h*c*(1/lamda - 1/lambda_)\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of x-ray is %.4f A\\nMaximum kinetic energy %.2e J\"%(lambda_ * 1e10,E_k)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of x-ray is 0.2485 A\n",
-        "Maximum kinetic energy 1.94e-15 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.29, Page 14.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "v = 96 # speed of automobile in km/hr\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 2e3 # mass of automobile in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v_ = v * (5. / 18)\n",
-      "lamda = h / (m * v_)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength is %.2e m\"%lamda\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength is 1.24e-38 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.30, Page 14.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 50 # potential differece in volt\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda =  h  / sqrt(2 * m * v * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength is %.2f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength is 1.73 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.31, Page 14.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 300 # temperature in K\n",
-      "k = 1.37e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of neutron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = h / sqrt(3 * m * k * t)\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of thermal neutron is %.3f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of thermal neutron is 1.459 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.32, Page 14.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "v = 2e8 # speed of proton in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of proton in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = h / (m * v)\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of matter wave associated with proton is %.2e m\"%lamda\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of matter wave associated with proton is 1.98e-15 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.33, Page 14.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 0.1e-10 # DE Broglie wavelength associated with electron in M\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "V = h**2 / (2 * m* e * lamda**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Potential difference is %.2f KV\"%(V * 10**-3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Potential difference is 15.05 KV\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.34, Page 14.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 200 # potential differece in volt\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "q = 3.2e-19 # charge on an alpha particle in C \n",
-      "m = 4 * 1.67e-27 # mass of alpha particle in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda =  h  / sqrt(2 * m * v * q)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength = %.2e m\"%lamda\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength = 7.16e-13 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.35, Page 14.34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 400 # temperature in K\n",
-      "k = 1.38e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 4 * 1.67e-27 # mass of helium atom in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = h / sqrt(3 * m * k * t)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength = %.4f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength = 0.6294 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.36, Page 14.35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "v = 2000 # velocity of neutron in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of neutron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = h / (m * v)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength is %.2f A\"%(lamda * 1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength is 1.98 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.37, Page 14.35"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 1e-10 # wavelength in m\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "m_ = 1.7e-27 # mass of neutron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v = h / (m_ * lamda)\n",
-      "E = h**2 / (2 * m * lamda**2)\n",
-      "E_ = h**2 / (2 * m_ * lamda**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy for electron is %.f eV\\nEnergy for neutron is %.3f eV\"%(E / e,E_ / e)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy for electron is 150 eV\n",
-        "Energy for neutron is 0.081 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.38, Page 14.36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E1 = 500 # kinetic energy of electron in first case in eV\n",
-      "E2 = 50 # kinetic energy of electron in second case in eV\n",
-      "E3 = 1 # kinetic energy of electron in third case in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lambda1 = h / sqrt(2 * m * E1 * e)\n",
-      "lambda2 = h / sqrt(2 * m * E2 * e)\n",
-      "lambda3 = h / sqrt(2 * m * E3 * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength of electron - \\n(1) In first case is %.4f A \\n(2) In second case is %.3f A \\n(3) In third is %.3f A\"%(lambda1*1e10,lambda2*1e10,lambda3*1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength of electron - \n",
-        "(1) In first case is 0.5486 A \n",
-        "(2) In second case is 1.735 A \n",
-        "(3) In third is 12.268 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.39, Page 14.36"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E1 = 1 # kinetic energy of neutron in first case in eV\n",
-      "E2 = 510 # kinetic energy of neutron in second case in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of neutron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lambda1 = h / sqrt(2 * m * E1 * e)\n",
-      "lambda2 = h / sqrt(2 * m * E2 * e)\n",
-      "r = lambda1 / lambda2\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of de-Broglie wavelengths is %.2f:1\"%r\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of de-Broglie wavelengths is 22.58:1\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.40, Page 14.37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 20 # kinetic energy of proton in MeV\n",
-      "E2 = 510 # kinetic energy of neutron in second case in eV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of proton in kg\n",
-      "m_ = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lambda1 = h / sqrt(2 * m * 10**6 * E * e)\n",
-      "lambda2 = h / sqrt(2 * m_ * E * 10**6 * e)\n",
-      "r = lambda2 / lambda1\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of de-Broglie wavelengths is 1:%.f\"%r\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of de-Broglie wavelengths is 1:43\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.41, Page 14.37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 1 # kinetic energy of proton in MeV\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of proton in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v = sqrt(2 * E * 1.6e-13 / m)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity is %.2e m/sec\"%v\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity is 1.38e+07 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.42, Page 14.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "r = 1. / 20 # ratio of velocity of proton to the velocity of light \n",
-      "c = 3e8 # velocity of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of proton in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v = r * c\n",
-      "lamda = h / (m * v)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength is %.3e m\"%lamda\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength is 2.643e-14 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 27
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.43, Page 14.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 5.0e-7 # wavelength in m\n",
-      "c = 3.e8 # velocity of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 1.67e-27 # mass of proton in kg\n",
-      "m_ = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "E1 = h**2 / (2 * m * lamda**2)\n",
-      "E2 = h**2 / (2 * m_ * lamda**2)\n",
-      "\n",
-      "#Results\n",
-      "print 'kinetic energy of proton(in J) =%.3e'%E1\n",
-      "print 'kinetic energy of electron(in J) =%.2e'%E2\n",
-      "      "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "kinetic energy of proton(in J) =5.248e-28\n",
-        "kinetic energy of electron(in J) =9.63e-25\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.44, Page 14.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "n = 1 # no. of Bohr's orbit of hydrogen atom\n",
-      "c = 3e8 # velocity of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "E = (13.6 / n**2) * e\n",
-      "lamda = h / sqrt(2 * m * E)\n",
-      "\n",
-      "#Result\n",
-      "print \"de-Broglie wavelength is %.1f A\"%(lamda*1e10)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "de-Broglie wavelength is 3.3 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.45, Page 14.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 300 # temperature in K\n",
-      "k = 1.376e-23 # Boltzmann's constant in J/K\n",
-      "c = 3e8 # velocity of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m_ = 4 * 1.67e-27 # mass of helium atom in kg\n",
-      "m = 1.67e-27 # mass of hydrogen atom in kg\n",
-      "\n",
-      "#Calculations\n",
-      "lambda1 = h / sqrt(3 * m * k * t)\n",
-      "lambda2 = h / sqrt(3 * m_ * k * t)\n",
-      "r = lambda1 / lambda2\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of de-Broglie wavelengths is %d:1\"%r\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of de-Broglie wavelengths is 2:1\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14.47, Page 14.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lamda = 1.2e-10 # DE Broglie wavelength in m\n",
-      "c = 3e8 # velocity of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C \n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "v1 = h / (m * lamda)\n",
-      "v2 = h / (2 * m * lamda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Group velocity is %.2e m/sec\\nPhase velocity is %.2e m/sec\"%(v1,v2)\n",
-      "                                                               "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Group velocity is 6.06e+06 m/sec\n",
-        "Phase velocity is 3.03e+06 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_15.ipynb b/Engineering_Physics/Chapter_15.ipynb
deleted file mode 100755
index 2b3eeafd..00000000
--- a/Engineering_Physics/Chapter_15.ipynb
+++ /dev/null
@@ -1,983 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 15: Quantum Mechanics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.1, Page 15.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 1000 # energy of electron in eV\n",
-      "delta_x = 1e-10 # error in position in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "p = sqrt(2 * m * E * e)\n",
-      "delta_p = h / (4 * pi * delta_x)\n",
-      "P = (delta_p / p) * 100\n",
-      "\n",
-      "#Result\n",
-      "print \"Percentage of uncertainty in momentum is %.1f%%\"%P"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Percentage of uncertainty in momentum is 3.1%\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.3, Page 15.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "E = 500 # energy of electron in eV\n",
-      "delta_x = 2e-10 # error in position in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "p = sqrt(2 * m * E * e)\n",
-      "delta_p = h / (4 * pi * delta_x)\n",
-      "P = (delta_p / p) * 100\n",
-      "\n",
-      "#Result\n",
-      "print \"Percentage of uncertainty in momentum is %.2f%%\"%P"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Percentage of uncertainty in momentum is 2.18%\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.4, Page 15.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "delta_lambda = 1e-6 # accuracy in wavelength of its one part\n",
-      "lamda = 1e-10 # wavelength of x-ray in m\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_x = lamda / (4 * pi * delta_lambda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in position is %.2f micrometer\"%(delta_x*10**6)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in position is 7.96 micrometer\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.5, Page 15.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "delta_x = 1e-10 # error in position in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_p = h / (4 * pi * delta_x)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in momentum is %.2e kg m/sec\"%delta_p"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in momentum is 5.27e-25 kg m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.6, Page 15.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "M = 5.4e-26 # momentum of electron in kg-m/sec\n",
-      "p = 0.05 # percentage accuracy in momentum\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_m = p * M / 100\n",
-      "delta_x = h / (4 * pi * delta_m)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in position is %.3f micrometer\"%(delta_x * 10**6)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in position is 1.951 micrometer\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.7, Page 15.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 0.53e-10 # radius of hydrogen atom in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_M = h / (4 * pi * r)\n",
-      "delta_k = delta_M**2 / (2 * m)\n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum energy of electron is %.3e J\"%delta_k"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum energy of electron is 5.428e-19 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.8, Page 15.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 5e3 # speed of electron in m/sec\n",
-      "a = 0.003 # percentage accuracy in measurement of speed \n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_v = v * a / 100\n",
-      "delta_p = m * delta_v\n",
-      "delta_x = h / (4 * pi * delta_p)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in determining the position of electron is %.3e m\"%delta_x"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in determining the position of electron is 3.859e-04 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.9, Page 15.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 6.6e4 # speed of electron in m/sec\n",
-      "a = 0.01 # percentage accuracy in measurement of speed \n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.6e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_v = v * a / 100\n",
-      "delta_p = m * delta_v\n",
-      "delta_x = h / (4 * pi * delta_p)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in determining the position is %.2e m\"%delta_x"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in determining the position is 8.74e-06 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.10, Page 15.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "v = 3e7 # speed of electron in m/sec \n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_p = m * v / sqrt(1 - (v/c)**2)\n",
-      "delta_x = h / (4 * pi * delta_p)\n",
-      "\n",
-      "#Result\n",
-      "print \"Uncertainty in determining the position is %.2e m\"%delta_x"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Uncertainty in determining the position is 1.92e-12 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.11, Page 15.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "t = 2.5e-14 # life time of hydrogen atom in exited state in sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_E = h / (4 * pi * t)\n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum error in measurement of the energy is %.2e J\"%delta_E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum error in measurement of the energy is 2.11e-21 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.12, Page 15.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 10**-8 # life time of atom in exited state in sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_f = 1 / (4 * pi * t)\n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum uncertainty in frequency is %.2e sec\"%delta_f"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum uncertainty in frequency is 7.96e+06 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.13, Page 15.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "delta_x = 20e-10 # uncertainty in position in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "m_ = 1.67e-27 # mass of proton in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "delta_v1 = h / (4 * pi * m * delta_x)\n",
-      "delta_v2 = h / (4 * pi * m_ * delta_x)\n",
-      "r = delta_v2 / delta_v1\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of uncertainty in velocity of a proton and an electron is %.2e\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of uncertainty in velocity of a proton and an electron is 5.45e-04\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.14, Page 15.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "delta_x = 1e-10 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "n = 1 # for n=1\n",
-      "\n",
-      "#Calculations\n",
-      "E = (n**2 * h**2) / (8 * m * delta_x**2)\n",
-      "n = 2 # for n=2\n",
-      "E_ = (n**2 * h**2) / (8 * m * delta_x**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of electron - \\nFor (n=1) energy is %.2e J\\nFor (n=2) energy is %.2e J\"%(E,E_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of electron - \n",
-        "For (n=1) energy is 6.02e-18 J\n",
-        "For (n=2) energy is 2.41e-17 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.15, Page 15.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "l = 1e-10 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "n = 1 # for n=1\n",
-      "\n",
-      "#Calculations\n",
-      "E = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 2 # for n=2\n",
-      "E_ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "d = E_ - E\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy difference is %.2e J\"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy difference is 1.81e-17 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.16, Page 15.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 3e-10 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "n = 1 # For n=1\n",
-      "\n",
-      "#Calculations\n",
-      "E = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 2 # For n=2\n",
-      "E_ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 3 # For n=3\n",
-      "E__ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of electron -\\nFor (n=1) is %.1e J\\nFor (n=2) is %.2e J\\nFor (n=3) is %.2e J\"%(E,E_,E__)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of electron -\n",
-        "For (n=1) is 6.7e-19 J\n",
-        "For (n=2) is 2.68e-18 J\n",
-        "For (n=3) is 6.02e-18 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.17, Page 15.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 2.5e-10 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "E = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 2 # for n=2\n",
-      "E_ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of electron -\\nFor (n=1) is %.2e J\\nFor (n=2) is %.3e J\"%(E,E_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of electron -\n",
-        "For (n=1) is 9.63e-19 J\n",
-        "For (n=2) is 3.853e-18 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.18, Page 15.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 1e-14 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 1.67e-27 # mass of neutron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "E = (h**2) / (8 * m * l**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Lowest energy of neutron confined in the nucleus is %.2e J\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Lowest energy of neutron confined in the nucleus is 3.28e-13 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.19, Page 15.31"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 1e-10 # width of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.63e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "p1 = (n * h) / (2 * l)\n",
-      "E = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 2 # for n=2\n",
-      "p2 = (n * h) / (2 * l)\n",
-      "E_ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy of electron -\\nFor (n=1) is %.2e J\\nFor (n=2) is %.2e J\"%(E,E_)\n",
-      "print \"\\nMomentum of electron -\\nFor (n=1) is %.3e kg-m/sec\\nFor (n=2) is %.2e kg-m/sec\"%(p1,p2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy of electron -\n",
-        "For (n=1) is 6.04e-18 J\n",
-        "For (n=2) is 2.42e-17 J\n",
-        "\n",
-        "Momentum of electron -\n",
-        "For (n=1) is 3.315e-24 kg-m/sec\n",
-        "For (n=2) is 6.63e-24 kg-m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.20, Page 15.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 1e-10 # length of box in m\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "E1 = (n**2 * h**2) / (8 * m * l**2)\n",
-      "lambda1 =2*l\n",
-      "n = 2 # for n=2\n",
-      "E2 = (n**2 * h**2) / (8 * m * l**2)\n",
-      "lambda2 =2*l/2\n",
-      "n = 3 # for n=3\n",
-      "E3 = (n**2 * h**2) / (8 * m * l**2)\n",
-      "lambda3 =2*l/3\n",
-      "\n",
-      "#Results\n",
-      "print \"Energy Eigen value of electron -\\nFor (n=1) is %.2e J\\nFor (n=2) is %.2e J\\nFor (n=3) is %.2e J\"%(E1,E2,E3)\n",
-      "print \"\\nde-Broglie wavelength of electron -\\nFor (n=1) is %.f A\\nFor (n=2) is %.f A \\nFor (n=3) is %.3f A\"%(lambda1*1e10,lambda2*1e10,lambda3*1e10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy Eigen value of electron -\n",
-        "For (n=1) is 6.02e-18 J\n",
-        "For (n=2) is 2.41e-17 J\n",
-        "For (n=3) is 5.42e-17 J\n",
-        "\n",
-        "de-Broglie wavelength of electron -\n",
-        "For (n=1) is 2 A\n",
-        "For (n=2) is 1 A \n",
-        "For (n=3) is 0.667 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.21, Page 15.32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E1 = 3.2e-18 # minimum energy possible for a particle entrapped in a one dimensional box in J\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "E1 = E1 / e # in eV\n",
-      "n = 2 # for n=2\n",
-      "E2 = n**2 * E1\n",
-      "n = 3 # for n=3\n",
-      "E3 = n**2 * E1\n",
-      "n = 4 # for n=4\n",
-      "E4 = n**2 * E1\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy Eigen values -\\nFor (n=2) for %.f eV\\nFor (n=3) is %.f eV\\nFor (n=4) is %.f eV\"%(E2,E3,E4)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy Eigen values -\n",
-        "For (n=2) for 80 eV\n",
-        "For (n=3) is 180 eV\n",
-        "For (n=4) is 320 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.22, Page 15.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "l = 4e-10 # width of box in m\n",
-      "E = 9.664e-17 # energy of electron in J\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "E1 = (n**2 * h**2) / (8 * m * l**2)\n",
-      "N = sqrt(E / E1)\n",
-      "p = ((N) * h) / (2 * l)\n",
-      "\n",
-      "#Result\n",
-      "print \"Order of exited state is %d\\nMomentum of electron is %.2e kg-m/sec\"%(N,p)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Order of exited state is 16\n",
-        "Momentum of electron is 1.33e-23 kg-m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15.23, Page 15.33"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 10e-10 # width of box containing electron in m\n",
-      "E = 9.664e-17 # energy of electron in J\n",
-      "M = 0.001 # mass of glass marble in kg\n",
-      "l_ = 0.2 # width of box containing marble in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "# For electron\n",
-      "n = 1 # for n=1\n",
-      "E1 = (n**2 * h**2) / (8 * m * l**2)\n",
-      "E2 = 2**2* E1\n",
-      "E3 = 3**2 * E1\n",
-      "# For glass marble\n",
-      "E1_ = h**2/(8*M*l_**2)\n",
-      "E2_ = 2**2 * E1_\n",
-      "E3_ = 3**2 *E1_\n",
-      "\n",
-      "#Result\n",
-      "print \"\\nEnergy levels of electron- \\nFor (n=1) is %.2e J\\nFor (n=2) is %.2e J\\n For (n=3) is %.2e J\"%(E1,E2,E3)\n",
-      "print \"\\nEnergy levels of marble- \\nFor (n=1) is %.2e J\\nFor (n=2) is %.2e J\\nFor (n=3) is %.2e J\"%(E1_,E2_,E3_)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "\n",
-        "Energy levels of electron- \n",
-        "For (n=1) is 6.02e-20 J\n",
-        "For (n=2) is 2.41e-19 J\n",
-        " For (n=3) is 5.42e-19 J\n",
-        "\n",
-        "Energy levels of marble- \n",
-        "For (n=1) is 1.37e-63 J\n",
-        "For (n=2) is 5.48e-63 J\n",
-        "For (n=3) is 1.23e-62 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_16.ipynb b/Engineering_Physics/Chapter_16.ipynb
deleted file mode 100755
index 0fab1922..00000000
--- a/Engineering_Physics/Chapter_16.ipynb
+++ /dev/null
@@ -1,467 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 16: Free Electron Theory"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.1, Page 16.14"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 0 # temperature in K\n",
-      "E = 10 # Fermi energy of electron in eV\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 3 / 5\n",
-      "v = sqrt(2 * E_ * e / m)\n",
-      "\n",
-      "#Result\n",
-      "print \"\\nAverage energy of electron is %.f eV\\nSpeed of electron is %.2e m/sec\"%(E_,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "\n",
-        "Average energy of electron is 6 eV\n",
-        "Speed of electron is 1.45e+06 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.2, Page 16.14"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "t = 0 # temperature in K\n",
-      "E = 7.9 # Fermi energy in eV\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "E_ = E * 3 / 5\n",
-      "v = sqrt(2 * E_ * e / m)\n",
-      "\n",
-      "#Result\n",
-      "print \"Average energy of electron is %.2f eV\\nSpeed of electron is %.2e m/sec\"%(E_,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Average energy of electron is 4.74 eV\n",
-        "Speed of electron is 1.29e+06 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.3, Page 16.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "n = 2.5e28 # no. of free electron in per meter cube\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "E = (h**2 / (8 * pi**2 * m)) * (3 * pi**2 * n)**(2./3) * (1. / e)\n",
-      "v = (h / (2 * pi * m)) * (3 * pi**2 * n)**(1./3)\n",
-      "\n",
-      "#Results\n",
-      "print \"Fermi energy is %.2f eV\\nSpeed of electron is %.2e m/sec\"%(E,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fermi energy is 3.12 eV\n",
-        "Speed of electron is 1.05e+06 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.4, Page 16.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 8940 # density of copper in kg/m^3\n",
-      "w = 63.55 # atomic weight of copper\n",
-      "t = 0 # temperature in K\n",
-      "N = 6.02e26 # Avogadro no. in per kg\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "V = w / d\n",
-      "n = N / V \n",
-      "E = (h**2 / (8 * pi**2 * m)) * (3 * pi**2 * n)**(2./3) * (1. / e)\n",
-      "E_ = 3 * E / 5\n",
-      "\n",
-      "#Results\n",
-      "print \"Fermi energy is %.3f eV\\nAverage energy is %.2f eV\"%(E,E_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fermi energy is 7.036 eV\n",
-        "Average energy is 4.22 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.5, Page 16.16\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 10.5e6 # density of silver in g/m^3\n",
-      "w = 108 # atomic weight of silver\n",
-      "t = 0 # temperature in K\n",
-      "N = 6.02e23 # Avogadro no. in per kg\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "V = w / d\n",
-      "n = N / V \n",
-      "E = (h**2 / (8 * pi**2 * m)) * (3 * pi**2 * n)**(2./3) * (1 / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Fermi energy is %.1f eV\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fermi energy is 5.5 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.6, Page 16.16"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "a = 4e-10 # lattice constant in mr\n",
-      "t = 0 # temperature in K\n",
-      "N = 6.02e23 # Avogadro no. in per kg\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "V = a**3\n",
-      "n = 4 / V \n",
-      "E = (h**2 / (8 * pi**2 * m)) * (3 * pi**2 * n)**(2./3) * (1 / e)\n",
-      "k = (3 * pi**2 *n)**(1./3)\n",
-      "KE = (3 * E / 5) * (n)\n",
-      "\n",
-      "#Results\n",
-      "print \"Fermi energy is %.2f eV\\nFermi vector is %.2e per m\\nTotal kinetic energy is %.2e eV\"%(E,k,KE)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fermi energy is 5.75 eV\n",
-        "Fermi vector is 1.23e+10 per m\n",
-        "Total kinetic energy is 2.15e+29 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.7, Page 16.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "d = 0.9e-3 # diameter of aluminium in m\n",
-      "i = 6 # current in amp\n",
-      "n = 4.5e28 # no. of electron available for conduction per meter^3 \n",
-      "e =  1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "J = i * 4 / (pi * (d)**2)\n",
-      "v = J / (n * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Drift velocity of electron is %.3e m/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Drift velocity of electron is 1.310e-03 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.8, Page 16.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 8.92e3 # density of copper in kg/m^3\n",
-      "i = 5 # current in amp\n",
-      "w = 63.5 # atomic weight of copper\n",
-      "r = 0.7e-3 # radius in meter\n",
-      "N = 6.02e28 # Avogadro no.\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "V = (w / d)\n",
-      "n = N / V \n",
-      "J = i / (pi * r**2)\n",
-      "v = J / (n * e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Current density = %.2e amp/m^2\\nDrift velocity is %.1e m/sec\"%(J,v)\n",
-      "#Incorrect units in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Current density = 3.25e+06 amp/m^2\n",
-        "Drift velocity is 2.4e-06 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.9, Page 16.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given\n",
-      "d1= 0.534*10**3 # densiy of Li in kg/m^3\n",
-      "d2= 0.971*10**3 # densiy of Na in kg/m^3\n",
-      "d3= 0.86*10**3 # densiy of K in kg/m^3\n",
-      "w1 = 6.939 # atomic weight of Li \n",
-      "w2 = 22.99 # atomic weight of Na\n",
-      "w3 = 39.202 # atomic weight of K\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "NA = 6.023e26 # Avogadro no.\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "# For Li\n",
-      "n1 = NA * d1/w1\n",
-      "E1 = h**2/(8*pi**2*m)*(3*pi**2*n1)**(2./3)\n",
-      "# For Na\n",
-      "n2 = NA * d2/w2\n",
-      "E2 = h**2/(8*pi**2*m)*(3*pi**2*n2)**(2./3)\n",
-      "# For K\n",
-      "n3 = NA * d3/w3\n",
-      "E3 = h**2/(8*pi**2*m)*(3*pi**2*n3)**(2./3)\n",
-      "\n",
-      "#Results\n",
-      "print \"Fermi Energy \\nFor Li is %.2f eV\\nFor Na is %.3f eV \\nFor K is %.3f eV\"%(E1/e,E2/e,E3/e)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Fermi Energy \n",
-        "For Li is 4.71 eV\n",
-        "For Na is 3.156 eV \n",
-        "For K is 2.039 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16.10, Page 16.18\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 1e-10 #length of box in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "h = 6.62e-34 # Planck constant in J-sec\n",
-      "\n",
-      "#Calculations\n",
-      "n = 1 # for n=1\n",
-      "E = (n**2 * h**2) / (8 * m * l**2)\n",
-      "n = 2 # for n=2\n",
-      "E_ = (n**2 * h**2) / (8 * m * l**2)\n",
-      "d = (E_ - E) * (1 / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy difference is %.2f eV\"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy difference is 112.87 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_17.ipynb b/Engineering_Physics/Chapter_17.ipynb
deleted file mode 100755
index 01028f54..00000000
--- a/Engineering_Physics/Chapter_17.ipynb
+++ /dev/null
@@ -1,258 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 17: Band Theory of Solids"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.1, Page 17.18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "a = 3e-10 # side of square lattice in m\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "p = (h / (2 * a))\n",
-      "E = (p**2 / (2 * m)) * (1. / e)\n",
-      "\n",
-      "#Result\n",
-      "print \"Electron momentum value at the sides of first Brilloin zone is %.1e kg-m/sec\\nEnergy of free electron is %.1f eV\"%(p,E)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Electron momentum value at the sides of first Brilloin zone is 1.1e-24 kg-m/sec\n",
-        "Energy of free electron is 4.2 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.2, Page 17.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import log,pi\n",
-      "\n",
-      "# Given \n",
-      "n = 5e22 # no. of atoms per m^3\n",
-      "t = 300 # room temperature in K\n",
-      "k = 1.37e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "d = (k * t) * log(n * h**3 / (2 * (2 * pi * m * k * t)**(3./2)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Position of fermi level is %.3f eV\"%(-d/e)\n",
-      "#Answer varies due to round-off errors"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Position of fermi level is 0.159 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.3, Page 17.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E = 0.3 # Fermi energy in eV\n",
-      "T = 330 # temperature in K\n",
-      "t = 300 # room temperature in K\n",
-      "k = 1.37e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "d = (T / t) * (E)\n",
-      "\n",
-      "print \"New position of fermi level is %.2f eV\"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "New position of fermi level is 0.30 eV\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.4, Page 17.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given\n",
-      "E = 0.7 # band gap for semiconductor in eV\n",
-      "t = 300 # room temperature in K\n",
-      "k = 1.38e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "n = 2 * ((2 * pi * k * t * m) / h**2)**(3./2) * exp(-(E * e / (2 * k * t)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Density of holes and electron is %.1e per m^3\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Density of holes and electron is 3.4e+19 per m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.5, Page 17.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "n = 5e28 # no. of atoms in per m^3\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "R = -(1 / (n * e))\n",
-      "\n",
-      "#Resilt\n",
-      "print \"Hall coefficient is %.3e m^3/C\"%R"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Hall coefficient is -1.250e-10 m^3/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17.6, Page 17.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "a = 4.28e-10 # cell side of Na in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "n = (2 / a**3)\n",
-      "R = -(1 / (n * e))\n",
-      "\n",
-      "#Result\n",
-      "print \"Hall coefficient is %.3e m^3/C\"%R"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Hall coefficient is -2.450e-10 m^3/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_18.ipynb b/Engineering_Physics/Chapter_18.ipynb
deleted file mode 100755
index de6fffda..00000000
--- a/Engineering_Physics/Chapter_18.ipynb
+++ /dev/null
@@ -1,876 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 18: Magnetic Properties of Solids"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.1, Page 18.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "r = 0.53e-10 # radius of orbit in m\n",
-      "f = 6.6e15 # frequency of revolution in Hz\n",
-      "h = 6.6e-34 # Planck constant in J sec\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "\n",
-      "#Calculations\n",
-      "M = e * f * pi * r**2\n",
-      "mu = (e * h) / (4 * pi * m) \n",
-      "\n",
-      "#Result\n",
-      "print \"Magnetic moment is %.3e Am^2\\nBohr magneton is %.2e J/T\"%(M,mu)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetic moment is 9.319e-24 Am^2\n",
-        "Bohr magneton is 9.23e-24 J/T\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.2, Page 18.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "X = -4.2e-6 # magnetic susceptibility\n",
-      "H = 1.19e5 # magnetic field in A/m\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "I = X * H\n",
-      "B = mu_ * (H + I)\n",
-      "mur = (1 + I/H)\n",
-      "\n",
-      "#Results\n",
-      "print \"Magnetisation is %.2f A/m\\nFlux density is %.3f T\\nRelative permeability is %.2f\"%(I,B,mur)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetisation is -0.50 A/m\n",
-        "Flux density is 0.150 T\n",
-        "Relative permeability is 1.00\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.3, Page 18.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "X = 1.2e-5 # magnetic susceptibility of magnesium\n",
-      "\n",
-      "#Calculations\n",
-      "p = 100 * X\n",
-      "\n",
-      "#Result\n",
-      "print \"Percentage increase in magnetic induction is %.4f percent\"%p"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Percentage increase in magnetic induction is 0.0012 percent\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.4, Page 18.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "X = -0.4e-5 # magnetic susceptibility of material\n",
-      "H = 1e4 # magnetic field in A/m\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permittivity of space\n",
-      "\n",
-      "#Calculations\n",
-      "I = X * H\n",
-      "B = mu_ * (H + I)\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnetisation is %.2f A/m\\nMagnetic flux density is %f T\"%(I,B)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetisation is -0.04 A/m\n",
-        "Magnetic flux density is 0.012566 T\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.5, Page 18.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "X = 2.3e-5 # magnetic susceptibility of aluminium\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "mur = 1 + X\n",
-      "mu = mu_ * mur\n",
-      "\n",
-      "#Result\n",
-      "print \"Permeability of aluminium is %.2e N/A^2\"%mu"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Permeability of aluminium is 1.26e-06 N/A^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.6, Page 18.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "X = 9.4e-2 # magnetic susceptibility\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "mu_r = 1 + X\n",
-      "mu = mu_ * mu_r\n",
-      "\n",
-      "#Results\n",
-      "print \"Absolute permeability is %.2e N/A^2\\nRelative permeability is %.3f\"%(mu,mu_r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Absolute permeability is 1.37e-06 N/A^2\n",
-        "Relative permeability is 1.094\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.7, Page 18.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "mu = 0.126 # maximum value of the permeability in N/A^2\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "mu_r = mu / mu_\n",
-      "X = mu_r - 1\n",
-      "\n",
-      "#Results\n",
-      "print \"Magnetic susceptibility is %.f\\nRelative permeability is %e\"%(X,mu_r)\n",
-      "#Answers differ due to rounding off values"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetic susceptibility is 100267\n",
-        "Relative permeability is 1.002676e+05\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.8, Page 18.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "r = 0.6e-10 # radius of the atom\n",
-      "N = 28e26 # no. of electron in per m^3\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "Z = 2 # atomic no. of helium\n",
-      "m = 9.1e-31 # mass of an electron in kg\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "Chi = -(mu_ * Z * N * r**2 * e**2) / (6 * m)\n",
-      "\n",
-      "#Result\n",
-      "print \"Diamagnetic susceptibility is %.3e\"%Chi"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diamagnetic susceptibility is -1.188e-07\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.9, Page 18.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "H = 1e3 # magnetisation field in A/m\n",
-      "phi = 2e-5 # magnetic flux in Weber\n",
-      "a = 0.2e-4 # area of cross section in m^2\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "B = phi / a\n",
-      "mu = B / H\n",
-      "X = mu / mu_ - 1\n",
-      "\n",
-      "#Results\n",
-      "print \"Permeability is %.e N/A^2\\nSusceptibility is %.3f\"%(mu,X)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Permeability is 1e-03 N/A^2\n",
-        "Susceptibility is 794.775\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.10, Page 18.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 1 # length of iron rod in m\n",
-      "a = 4e-4 # area in m^2\n",
-      "mu = 50e-4 # permeability of iron in H/m\n",
-      "Phi = 4e-4 # magnetic flux in Weber\n",
-      "\n",
-      "#Calculations\n",
-      "B = Phi / a\n",
-      "NI = B / mu\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of ampere turns is %d A/m\"%NI"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of ampere turns is 200 A/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.11, Page 18.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "n = 200 # no. of turns \n",
-      "l = 0.5 # the mean length of iron wire in m\n",
-      "phi = 4e-4 # magnetic flux in Weber\n",
-      "a = 4e-4 # area of cross section in m^2\n",
-      "mu = 6.5e-4 # permeability of iron in wb/Am\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permeability of space\n",
-      "\n",
-      "#Calculations\n",
-      "B = phi / a\n",
-      "N = n / l\n",
-      "I = B / (mu * N)\n",
-      "\n",
-      "#Result\n",
-      "print \"Current through the winding is %.2f A\"%I"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Current through the winding is 3.85 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.12, Page 18.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "X = -5.6e-6 # magnetic susceptibility of material\n",
-      "a = 2.55e-10 # lattice constant in m\n",
-      "H = 1e4 # magnetic field in A/m\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permittivity of space\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "e = 1.6e-19 # charge in an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "N = 2 / a**3\n",
-      "z = 1 \n",
-      "R = ((-X * 6 * m) / (mu_ * z * e**2 * N))**(1./2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Radius of  atom is %.2f A\"%(R * 1e10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of  atom is 0.89 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.13, Page 18.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "N = 6.5e25 # no. of atom per m^3\n",
-      "T = 300 # room temperature in K\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permittivity of space\n",
-      "k = 1.38e-23 # Boltzmann's constant in J/K\n",
-      "m = 9.1e-31 # mass of electron in kg\n",
-      "e = 1.6e-19 # charge in an electron in C\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "\n",
-      "#Calculations\n",
-      "M = (e * h) / (4 * pi * m)\n",
-      "X = (mu_ * N * M**2) / (3 * k * T)\n",
-      "\n",
-      "#Result\n",
-      "print \"Susceptibility is %.3e\"%X"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Susceptibility is 5.642e-07\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.14, Page 18.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "w = 168.5 # molecular weight \n",
-      "d = 4370 # density of material in kg/m^3\n",
-      "H = 2e5 # magnetic field in A/m\n",
-      "T = 300 # room temperature in K\n",
-      "mu_ = 4 * pi * 1e-7 # magnetic permittivity of space]\n",
-      "NA = 6.02e26 # Avogadro no. in per kg\n",
-      "mu_b = 9.24e-24 # Bohr magnetons in Am^2\n",
-      "k = 1.38e-23 # Boltzmann's constant in J/K\n",
-      "\n",
-      "#Calculations\n",
-      "N = d * NA / w\n",
-      "X = (mu_ * N * (2 * mu_b)**2) / (3 * k * T)\n",
-      "I = X * H\n",
-      "\n",
-      "#Result\n",
-      "print \"Magnetisation is %.2f A/m\"%I"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Magnetisation is 107.89 A/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.15, Page 18.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given that\n",
-      "A = 2500 # area of hysteresis loop \n",
-      "m = 10000 # weight in kg\n",
-      "d = 7.5 # density of material in g/cm^3\n",
-      "f = 50 # frequency in Hz\n",
-      "\n",
-      "#Calculations\n",
-      "E = f * A * 3600\n",
-      "V = m / d\n",
-      "L = E * V\n",
-      "\n",
-      "#Result\n",
-      "print \"Total loss of energy per hour is %.e ergs\"%L"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Total loss of energy per hour is 6e+11 ergs\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.16, Page 18.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "H = 5e3 # coercivity in A/m\n",
-      "l = 0.10 # length of solenoid in m\n",
-      "n = 50 # no. of turns \n",
-      "\n",
-      "#Calculations\n",
-      "N = n / l\n",
-      "i = H / N\n",
-      "\n",
-      "#Result\n",
-      "print \"Current in solenoid should be %d A\"%i"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Current in solenoid should be 10 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.17, Page 18.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "l = 0.50 # length of iron rod in m\n",
-      "a = 4e-4 # area of cross section of rod in m^2\n",
-      "mu = 65e-4 # permeability of iron in H/m\n",
-      "fi = 4e-5 # flux in weber \n",
-      "\n",
-      "#Calculations\n",
-      "B = fi / a\n",
-      "H = B / mu\n",
-      "N = H * l\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of turns are %.2f\"%N"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of turns are 7.69\n"
-       ]
-      }
-     ],
-     "prompt_number": 27
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.18, Page 18.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "H = 600 # magnetic flux in A/m\n",
-      "a = 0.2e-4 # area of cross section of rod in m^2\n",
-      "phi = 2.4e-5 # flux in weber \n",
-      "mu_ = 4*pi * 1e-7 # permeability of space in N/A^2\n",
-      "\n",
-      "#Calculations\n",
-      "B = phi / a\n",
-      "mu = B / H\n",
-      "X = mu / mu_ - 1\n",
-      "\n",
-      "#Result\n",
-      "print \"Permeability is %.3f N/A^2\\nSusceptibility is %.f\"%(mu,X)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Permeability is 0.002 N/A^2\n",
-        "Susceptibility is 1591\n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.19, Page 18.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "X = 9.5e-9 # susceptibility of medium \n",
-      "mu_ = 4*pi * 1e-7 # permeability of space in N/A^2\n",
-      "\n",
-      "#Calculations\n",
-      "mu = mu_ * (1 + X)\n",
-      "mu_r = mu / mu_\n",
-      "\n",
-      "#Result\n",
-      "print \"Relative permeability is 1 + %.3e\"%(mu_r -1)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Relative permeability is 1 + 9.500e-09\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.20, Page 18.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "a = 250. # area of the B-H loop in J/m^3\n",
-      "f = 50. # frequency in Hz\n",
-      "d = 7.5e3 # density of iron in kg/m^3\n",
-      "m = 100. # mass of core in kg\n",
-      "\n",
-      "#Calculations\n",
-      "V = m / d\n",
-      "n = 3600 * f\n",
-      "A = a * V * n\n",
-      "\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy loss per hour is %.3e J\"%A\n",
-      "#Answer varies due to rounding-off values"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy loss per hour is 6.000e+05 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18.21, Page 18.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "B_max = 1.375 # maximum value of B in Wb/m^2\n",
-      "a = 0.513 # area of the loop in cm^2\n",
-      "k = 1000 # value of 1 cm on x axis in A/m\n",
-      "k_ = 1 # value of 1 cm on y axis in Wb/m^2\n",
-      "B = 1.375 # alternating magnetic flux density in Wb/m^2\n",
-      "v = 1e-3 # volume of specimen in m^3\n",
-      "f = 50 # frequency in Hz\n",
-      "\n",
-      "#Calculations\n",
-      "K = a * k * k_\n",
-      "L = K * v * f\n",
-      "\n",
-      "#Result\n",
-      "print \"Hysteresis loss per sec is %.2f W\"%L"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Hysteresis loss per sec is 25.65 W\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_19.ipynb b/Engineering_Physics/Chapter_19.ipynb
deleted file mode 100755
index 8e043325..00000000
--- a/Engineering_Physics/Chapter_19.ipynb
+++ /dev/null
@@ -1,333 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 19: Superconductivity"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.1, Page 19.13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "T_c = 7.2 # critical temperature in K\n",
-      "T = 5.1 # temperature in K\n",
-      "lambda_ = 380 # penetration depth at 0 K in A\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = lambda_ * (1 - (T / T_c)**4)**(-1./2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Penetration depth is %.2f A\"%lamda"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Penetration depth is 439.30 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.2, Page 19.13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "Hc1 = 1.41e5 # first critical field at 14.1K\n",
-      "Hc2 = 4.205e5 # second critical field at 12.9K \n",
-      "T1 = 14.11 # temperature in K\n",
-      "T2 = 12.9 # temperature in K \n",
-      "T = 4.2 # temperature in K\n",
-      "lambda_ = 380 # penetration depth at 0 K in A\n",
-      "\n",
-      "#Calculations\n",
-      "Tc = sqrt((Hc2*T1**2 - Hc1*T2**2) / (Hc2 - Hc1))\n",
-      "H_ = Hc1 / (1 - (T1 / Tc)**2)\n",
-      "Hc = H_ * (1 - (T/Tc)**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Transition temperature is %.2f K\\nCritical field at temperate at 4.2 k is %.2e A/m\"%(Tc,Hc)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Transition temperature is 14.68 K\n",
-        "Critical field at temperate at 4.2 k is 1.69e+06 A/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.3, Page 19.14"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "d = 1e-3 # diameter of wire in m\n",
-      "T1 = 4.2 # temperature in K\n",
-      "T2 = 7.18 # temperature in K\n",
-      "H_ = 6.51e4 # critical magnetic field at 0 K\n",
-      "\n",
-      "#Calculations\n",
-      "r = d / 2\n",
-      "Hc = H_ * (1 - (T1 / T2)**2)\n",
-      "Jc = (2 * pi * r * Hc) / (pi * r**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical current density is %.3e A/m^2\"%Jc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical current density is 1.713e+08 A/m^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.4, Page 19.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "w = 199.5 # isotopic mass of Hg\n",
-      "Tc = 4.186 # critical temperature in K \n",
-      "w_ = 203.4 # increased isotope mass of Hg\n",
-      "\n",
-      "#Calculations\n",
-      "Tc_ = Tc * (w / w_)**(1./2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical temperature is %.4f K\"%Tc_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical temperature is 4.1457 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.5, Page 19.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "T_c = 4.2 # critical temperature in K\n",
-      "T = 2.9 # temperature in K\n",
-      "lamda = 57 # penetration depth at 2.9 K in nm\n",
-      "\n",
-      "#Calculations\n",
-      "lambda_ = lamda * (1 - (T / T_c)**4)**(1./2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Penetration depth at 0 K is %.2f nm\"%lambda_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Penetration depth at 0 K is 50.10 nm\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.6, Page 19.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given\n",
-      "T1 = 2.18 # temperature in first case in K\n",
-      "lambda1 = 16 # penetration depth at 2.18 K in nm\n",
-      "T2 = 8.1 # temperature in second case in K\n",
-      "lambda2 = 96 # penetration depth at 8.1 K in nm\n",
-      "\n",
-      "#Calculations\n",
-      "Tc = (((lambda2**2 * T2**4) - (T1**4 * lambda1**2)) / (lambda2**2 - lambda1**2))**(1./4)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical temperature is %.2f K\"%Tc"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical temperature is 8.16 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.7, Page 19.16"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "w = 26.91 # isotopic mass of superconducting sample\n",
-      "Tc = 1.19 # first critical temperature in K \n",
-      "w_ = 32.13 # increased isotope mass of superconducting sample\n",
-      "\n",
-      "#Calculations\n",
-      "Tc_ = Tc * (w / w_)**(1./2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical temperature is %.3f K\"%Tc_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical temperature is 1.089 K\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19.8, Page 19.16"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "k = 1.38e-23 # Boltzmann's constant in J/K\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "Tc = 4.2 # critical temperature of Hg in K\n",
-      "c = 3e8 # speed of light in m/sec \n",
-      "\n",
-      "#Calculations\n",
-      "E = 3 * k * Tc\n",
-      "lamda = h * c / E\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy gap is %.2e eV\\nWavelength of photon is %.2e m\"%(E/1.6e-19,lamda)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy gap is 1.09e-03 eV\n",
-        "Wavelength of photon is 1.14e-03 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_2.ipynb b/Engineering_Physics/Chapter_2.ipynb
deleted file mode 100755
index dccc71e2..00000000
--- a/Engineering_Physics/Chapter_2.ipynb
+++ /dev/null
@@ -1,1712 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2: Diffraction"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.1, Page 2.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt,pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "d = 1 # distance of wavefront received on the screen from the opening in meter\n",
-      "n = 80 # no. of half period zone\n",
-      "\n",
-      "#Calculations\n",
-      "Rn = sqrt(n * l * d)# calculation for radius of nth half period zone\n",
-      "A = pi * d * l# calculation for area of half period zone\n",
-      "\n",
-      "#Result\n",
-      "print(\"Radius of 80th half period zone = %.3f cm. \\nArea of half period zone = %.4f square cm.\"%(Rn*100,A*10000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of 80th half period zone = 0.632 cm. \n",
-        "Area of half period zone = 0.0157 square cm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.2, Page 2.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "f = 0.6 # focal length of convex lens in meter\n",
-      "n = 1 # no. of half period zone\n",
-      "\n",
-      "#Calculation\n",
-      "Rn = sqrt(n * l * f)# calculation for radius of half period zone\n",
-      "\n",
-      "print(\"Radius of  half period zone = %.1f mm \"%(Rn*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of  half period zone = 0.6 mm \n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.3, Page 2.38"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "f = 0.60  #focal length in m\n",
-      "n = 1 # no. of half period zone\n",
-      "\n",
-      "#Calculation\n",
-      "r1 = sqrt(f* l ) # because at maxima intensity is four time the individual intensity of light\n",
-      "\n",
-      "#Result\n",
-      "print(\"Radius of 80th half period zone = %.4f mm. \"%(r1)) "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of 80th half period zone = 0.0006 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.4, Page 2.39"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "d = 0.5 # distance of observation point from circular opening in meter\n",
-      "r1 = 2e-3 # radius of circular opening in first case in meter\n",
-      "r2 = 2e-2 # radius of circular opening in second case in meter \n",
-      "\n",
-      "#Calculation\n",
-      "n1 = (r1**2) / (d * l) # calculation for no. of half period zone in first case \n",
-      "n2 = (r2**2) / (d * l) # calculation for no. of half period zone in second case\n",
-      "\n",
-      "print(\"No. of half period zone in first case = %d \\nNo. of half period zone in second case = %d \"%(n1,n2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of half period zone in first case = 13 \n",
-        "No. of half period zone in second case = 1333 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.5, Page 2.39"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "d = 1e-3 # diameter of the first ring of zone plate in meter\n",
-      "n = 1 # no. of half period zone\n",
-      "\n",
-      "#Calculation\n",
-      "D = (d**2) / (4 * l * n) # calculation for distance of screen from opening\n",
-      "\n",
-      "#Result\n",
-      "print(\"Distance of screen from opening = %.1f meter \"%D)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance of screen from opening = 0.5 meter \n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.6, Page 2.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "f = 1 # focal-length of convex lens in meter\n",
-      "n1 = 1 # no. of first half period zone\n",
-      "n2 = 3 # no. of second half period zone\n",
-      "n3 = 5 # no. of third half period zone\n",
-      "\n",
-      "#Calculations\n",
-      "R1 = sqrt(n1 * l * f) # calculation for Radius of first half period zone\n",
-      "R2 = sqrt(n2 * l * f) # calculation for Radius of second half period zone\n",
-      "R3 = sqrt(n3 * l * f) # calculation for Radius of third half period zone\n",
-      "\n",
-      "#Result\n",
-      "print(\"Radius of first ,second and third half period zone = %.3e, %.3e and %.3e meter respectively. \"%(R1,R2,R3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of first ,second and third half period zone = 7.677e-04, 1.330e-03 and 1.717e-03 meter respectively. \n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.7, Page 2.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "f = 0.2 # focal length of convex lens in meter\n",
-      "n = 10 # no. of half period zone\n",
-      "\n",
-      "#Calculation\n",
-      "Rn = sqrt(n * l * f) # calculation for radius of 10th half period zone\n",
-      "\n",
-      "#Result\n",
-      "print(\"Radius of 10th half period zone = %.1f mm. \"%(Rn*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of 10th half period zone = 1.0 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.8, Page 2.40"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "d1 = 1. # distance of wavefront recieved on the screen from the opening in first side in meter\n",
-      "d2 = 2. # distance of wavefront recieved on the screen from the opening in other side in meter\n",
-      "\n",
-      "#Calculations\n",
-      "f = (d1 * d2) / (d1 + d2)\n",
-      "p = 1. / f # beacause zone plate act as a convex lens\n",
-      "n = 1 # for first zone\n",
-      "Rn = sqrt(n * l * f) # calculation for radius of first zone\n",
-      "Dn = 2 * Rn # calculation for diameter of first zone\n",
-      "\n",
-      "#Result\n",
-      "print(\"Focal length = %.2f meter. \\n Power = %.1f D. \\n Diameter of first zone = %.3f mm. \"%(f,p,Dn*1000))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Focal length = 0.67 meter. \n",
-        " Power = 1.5 D. \n",
-        " Diameter of first zone = 1.253 mm. \n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.9, Page 2.41"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "lambda1 = 6e-7 # wavelength of first light in meter\n",
-      "lambda2 = 5e-7 # wavelength of second light in meter\n",
-      "f1 = 1 # focal length in first case in meter \n",
-      "\n",
-      "#Calculation\n",
-      "f2 = (lambda1 * f1) / lambda2 # calculation for focal length in second case\n",
-      "\n",
-      "#Result\n",
-      "print(\"Focal length in second case = %.1f meter\"%f2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Focal length in second case = 1.2 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.10, Page 2.41"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 4e-7 # wavelength of light in meter\n",
-      "u = 0.2 # distance of object from zone plate in meter\n",
-      "v = 0.2 # distance of brightest image from from zone plate in meter \n",
-      "r = 0.01 # radius in meter\n",
-      "\n",
-      "#Calculations\n",
-      "f = (u * v) / (u + v) # calculation for focal length\n",
-      "n = (r**2) / (f * l) # calculation for no. of zone of Fresnel\n",
-      "\n",
-      "#Result\n",
-      "print(\"No. of zone of Fresnel = %.f\"%n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of zone of Fresnel = 2500\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.11, Page 2.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "d = 2.3e-3 # diameter of the central zone of zone plate in meter\n",
-      "u = 6 # distance between point source from zone plate in meter\n",
-      "n = 1 # for central zone\n",
-      "\n",
-      "#Calculations\n",
-      "r = d/2\n",
-      "f = (r**2) / (l) # calculation for focal length\n",
-      "v = (f * u) / (u - f)  # calculation for distance of first image from zone plate\n",
-      "\n",
-      "#Result\n",
-      "print(\"Distance of first image from zone plate = %.2f meter \"%v) #answer differs due to rounding-off values"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Distance of first image from zone plate = 3.59 meter \n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.12, Page 2.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "R = 2 # radius of curvature in meter\n",
-      "\n",
-      "#Calculation\n",
-      "f = R # calculation for principal focal length of zone plate\n",
-      "\n",
-      "#Result\n",
-      "print(\"Principal focal length of zone plate = %.1f meter \"%f)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Principal focal length of zone plate = 2.0 meter \n"
-       ]
-      }
-     ],
-     "prompt_number": 43
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.13, Page 2.42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "b = 1e-3 # slit-width in meter\n",
-      "m = 1 # for first minima\n",
-      "\n",
-      "#Calculation\n",
-      "theta = asin((m * l) / b) # calculation for angular spread of the central maxima in radian\n",
-      "theta_ = theta * (180 / pi) # calculation for angular spread of the central maxima in degree\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angular spread of the central maxima = %.4f degree \"%(2 * theta_))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angular spread of the central maxima = 0.0675 degree \n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.14, Page 2.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d = 1.2 # distance of screen from slit in meter\n",
-      "x = 3.7e-3 # distance between first maxima to central maxima in meter\n",
-      "b = 2e-4 # slit-width in meter\n",
-      "\n",
-      "#Calculation\n",
-      "l = (x * b) / d # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of light = \",round(l/1e-10),\"A\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light =  6167.0 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 70
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.15, Page 2.43"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "b = 2.2e-6 # slit-width in meter\n",
-      "\n",
-      "#Calculations\n",
-      "m2 = 2 # for second minima\n",
-      "theta2 = asin((m2 * l) / b) * (180 / pi) # calculation for angular position of second minima\n",
-      "m3 = 3 # for third minima\n",
-      "theta3 = asin((m3 * l) / b) * (180 / pi) # calculation for angular position of third minima\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angular position of second and third minima = %.f degrees and %.2f degrees respectively \"%(theta2 ,theta3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angular position of second and third minima = 30 degrees and 48.59 degrees respectively \n"
-       ]
-      }
-     ],
-     "prompt_number": 72
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.16, Page 2.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "b = 1.2e-6 # slit-width in meter\n",
-      "\n",
-      "#Calculation\n",
-      "m = 1 # for first minima\n",
-      "theta = asin((m * l) / b) # calculation for half angular width of the central bright maxima in radian\n",
-      "theta_ = theta * (180 / pi) # calculation for half angular width of the central bright maxima in degree\n",
-      "\n",
-      "#Result\n",
-      "print(\"Half angular width of the central bright maxima = %.2f degrees \"%theta_)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Half angular width of the central bright maxima = 29.40 degrees \n"
-       ]
-      }
-     ],
-     "prompt_number": 74
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.17, Page 2.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sin, pi \n",
-      "\n",
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "theta = pi / 6 # half angular width of central maximum in first case in radian\n",
-      "theta_ = pi / 2 # half angular width of central maximum in second case in radian\n",
-      "\n",
-      "#Calculation\n",
-      "m = 1 # for first minima\n",
-      "b1 = (l * m) / sin(theta) # calculation for slit width in first case\n",
-      "b2 = (l * m) / sin(theta_) # calculation for slit width in second case\n",
-      "\n",
-      "#Result\n",
-      "print(\"Slit width in first case = %.f micro-meter \\nSlit width in second case = %.1f micro-meter\"%(b1*1e6,b2*1e6))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Slit width in first case = 1 micro-meter \n",
-        "Slit width in second case = 0.5 micro-meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.18, Page 2.44"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "d = 1 # distance of screen from slit in meter\n",
-      "b = 1e-4 # slit-width in meter\n",
-      "\n",
-      "#Calculations\n",
-      "theta = (asin(l / b)) * (180 / pi) # calculation for angular spread\n",
-      "x = (2 * d * l) / b# calculation for linear width\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angular spread = %.3f degree\\nLinear width = %.3f cm \"%(2*theta,x*1e2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angular spread = 0.675 degree\n",
-        "Linear width = 1.178 cm \n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.20, Page 2.45"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "b = 1.2e-6 # slit-width in meter\n",
-      "\n",
-      "#Calculations\n",
-      "m = 1 # for first minima\n",
-      "theta = asin((m * l) / b) # calculation for angular width of the central maxima in radian\n",
-      "theta_ = theta * (180 / pi) # calculation for angular width of the central maxima in degree\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angular width of the central maxima = %.f degree \"%(2 * theta_))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angular width of the central maxima = 60 degree \n"
-       ]
-      }
-     ],
-     "prompt_number": 104
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.21, Page 2.46"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 4.890e-7 # wavelength of light in meter\n",
-      "b = 5e-3 # slit-width in meter\n",
-      "f = 0.4 # focal-length of convex lens in meter\n",
-      "\n",
-      "#Calculation\n",
-      "m = 1 # for first dark fringe\n",
-      "x = (f * m * l) / b  \n",
-      "n = 1 # for first secondary maxima\n",
-      "x_ = ((2 * n + 1) * l * f) / (2 * b) \n",
-      "delta_x = x_ - x # calculation for separation of dark band \n",
-      "\n",
-      "#Result\n",
-      "print(\"Separation of dark band = %.3e meter.\"%(delta_x))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Separation of dark band = 1.956e-05 meter.\n"
-       ]
-      }
-     ],
-     "prompt_number": 105
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.22, Page 2.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "b = 5e-4 # slit-width in meter\n",
-      "f = 1 # focal length of convex lens in meter\n",
-      "\n",
-      "#Calculation\n",
-      "x = (2 * l * f) / b # calculation for Separation of dark band on either side of the cenral maximum\n",
-      "\n",
-      "#Result\n",
-      "print(\"Separation of dark band on either side of the central maximum = %.3e meter\"%x)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Separation of dark band on either side of the central maximum = 2.357e-03 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 106
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.23, Page 2.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d = 4e-4 # separation between slits in meter\n",
-      "b = 8e-5 # slit-width in meter\n",
-      "\n",
-      "#Calculations\n",
-      "r = (b + d) / b # calculation for ratio of n with m\n",
-      "m1 = 1\n",
-      "n1 = r * m1 # calculation for Missing orders \n",
-      "m2 = 2\n",
-      "n2 = r * m2 # calculation for Missing orders \n",
-      "m3 = 3\n",
-      "n3 = r * m3 # calculation for Missing orders \n",
-      "\n",
-      "#Result\n",
-      "print(\"Missing orders = %d,%d,%d,......etc.\"%(n1,n2,n3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Missing orders = 6,12,18,......etc.\n"
-       ]
-      }
-     ],
-     "prompt_number": 107
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.24, Page 2.47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "d = 4e-4 # separation between slits in meter\n",
-      "b = 2e-4 # slit-width in meter\n",
-      "fringe_width = 2.5e-3 # fringe width in meter\n",
-      "D = 1.6 # distance between screen and slits\n",
-      "\n",
-      "#Calculations\n",
-      "l = (fringe_width * d) / D # calculation for wavelength of light\n",
-      "r = (b + d) / b # calculation for ratio of n with m\n",
-      "m1 = 1\n",
-      "n1 = r * m1 # calculation for missing order\n",
-      "m2 = 2\n",
-      "n2 = r * m2 # calculation for missing order\n",
-      "m3 = 3\n",
-      "n3 = r * m3 # calculation for missing order\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light = %.3e meter. \\nMissing order = %d,%d,%d....etc.\"%(l,n1,n2,n3))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light = 6.250e-07 meter. \n",
-        "Missing order = 3,6,9....etc.\n"
-       ]
-      }
-     ],
-     "prompt_number": 109
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.25, Page 2.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sin\n",
-      "\n",
-      "# Given \n",
-      "N = 425000 # no. of lines in plane transmission grating per meter\n",
-      "theta = pi / 6 # angle at which second order spectral line is observed in radian\n",
-      "n = 2 # order of spectral line\n",
-      "\n",
-      "#Calculation\n",
-      "l = sin(theta) / (2 * N) # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of light = \",round(l/1e-10),\"A\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light =  5882.0 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 115
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.26, Page 2.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sin\n",
-      " \n",
-      "# Given \n",
-      "N = 500000 # no. of lines in plane transmission grating per meter\n",
-      "theta = pi / 6 # angle at which second order spectral line is observed in radian\n",
-      "n = 2 # order of spectral line\n",
-      "\n",
-      "#Calculation\n",
-      "l = sin(theta) / (2 * N) # calculation for wavelength of light\n",
-      "\n",
-      "#Result\n",
-      "print \"wavelength of light = \",l/1e-10,\"A\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "wavelength of light =  5000.0 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 116
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.27, Page 2.48"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import ceil\n",
-      "\n",
-      "# Given \n",
-      "lambda2 = 5.461e-7 # wavelength of  light in second case in meter\n",
-      "n1 = 4 # no. of order in first case\n",
-      "n2 = 3 # no. of order in second case \n",
-      "\n",
-      "#Calculation\n",
-      "lambda1 = (n2 * lambda2) / n1 # calculation for Wavelength of light in first case\n",
-      "\n",
-      "#Result\n",
-      "print(\"Wavelength of light in first case = %d A\"%(ceil(lambda1*1e10)))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of light in first case = 4096 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 90
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.28, Page 2.49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sin\n",
-      "\n",
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "theta = pi / 6 # angle at which second order spectral line is observed in radian\n",
-      "n = 2 # order of spectral line\n",
-      "\n",
-      "#Calculations\n",
-      "k = (n * l) / sin(theta) # calculation for (b+d)\n",
-      "N = 1 / k # calculation for no. of lines in per cm\n",
-      "\n",
-      "#Result\n",
-      "print(\"No. of lines per cm = %.f \"%(N / 100))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of lines per cm = 5000 \n"
-       ]
-      }
-     ],
-     "prompt_number": 117
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.29, Page 2.49"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin,pi \n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 5.048e-7 # wavelength of light in first case in meter\n",
-      "lambda2 = 5.016e-7 # wavelength of light in second case in meter\n",
-      "n = 2 # no. of order in first case\n",
-      "N = 15000 # no. of lines in grating per inch  \n",
-      "\n",
-      "#Calculations\n",
-      "k = 2.54 / 1500000 # in meter\n",
-      "theta1 = asin(n * lambda1 / k) * (180 / pi) # calculation for angle in first case\n",
-      "theta2 = asin(n * lambda2 / k) * (180 / pi) # calculation for angle in second case\n",
-      "delta_theta = theta1 - theta2 # calculation for angle of separation\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angle of separation = %.2f degree\"%delta_theta)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of separation = 0.27 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 118
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.30, Page 2.50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin,pi \n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 5.89e-7 # wavelength of  light in first case in meter\n",
-      "lambda2 = 5.896e-7 # wavelength of  light in second case in meter\n",
-      "n = 2 # no. of order in first case\n",
-      "N = 600000 # no. of lines in grating per meter  \n",
-      "\n",
-      "#Calculations\n",
-      "k = 1. / N # in meter\n",
-      "theta1 = asin(n * lambda1 / k) * (180 / pi) # calculation for angle in first case\n",
-      "theta2 = asin(n * lambda2 / k) * (180 / pi) # calculation for angle in second case\n",
-      "delta_theta = theta2 - theta1 # calculation for angle of separation\n",
-      "\n",
-      "#Result\n",
-      "print(\"Angle of separation = %.2f degree\"%delta_theta)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of separation = 0.06 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 119
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.31, Page 2.50"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 5.4e-7 # wavelength of light for nth order in meter\n",
-      "lambda2 = 4.05e-7 # wavelength of light for (n+1)th order in meter \n",
-      "theta = pi / 6 # angle of diffraction in radian \n",
-      "\n",
-      "#Calculations\n",
-      "k = (lambda1 * lambda2) / ((lambda1 - lambda2) * sin(theta)) # calculation for b+d\n",
-      "N = (1 / k) * (0.01) # calculation for no. of lines per cm\n",
-      "\n",
-      "#Result\n",
-      "print(\"No. of lines per cm = %d \"%N)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "No. of lines per cm = 3086 \n"
-       ]
-      }
-     ],
-     "prompt_number": 97
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.32, Page 2.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, cos, sin\n",
-      "\n",
-      "# Given \n",
-      "d_theta = 0.01 # angular separation between two wavelengths in radian \n",
-      "theta = pi / 6 # angle of diffraction in radian \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "d_lambda = (l * cos(theta) * d_theta) / sin(theta) # calculation for difference in two waveligth\n",
-      "\n",
-      "#Result\n",
-      "print \"Difference in two wavelength = \",round(d_lambda/1e-10,1),\"A\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Difference in two wavelength =  86.6 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 127
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.33, Page 2.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "N = 2620 # no. of lines in plane transmission grating per inch\n",
-      "l = 5e-7 # wavelength of incident radiation in meter\n",
-      "\n",
-      "#Calculations\n",
-      "k = 2.54 / N * 1 / 100 # calculation for b+d in meter\n",
-      "n = k / l # calculation for order of spectrum\n",
-      "\n",
-      "#Result\n",
-      "print(\"Order of spectrum = %d\"%n)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Order of spectrum = 19\n"
-       ]
-      }
-     ],
-     "prompt_number": 99
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.34, Page 2.51"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "N = 500000. # no. of lines in plane transmission grating per meter\n",
-      "l = 5e-7 # wavelength of incident radiation in meter\n",
-      "\n",
-      "#Calculations\n",
-      "k = 1 / N # calculation for b+d in meter\n",
-      "n = k / l # calculation for order of spectrum \n",
-      "\n",
-      "#Result\n",
-      "print \"Order of spectrum = %d\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Order of spectrum = 4\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.35, Page 2.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "N = 4000.       # no. of lines in plane transmission grating per meter\n",
-      "lambda1 = 4.e-7 # wavelength of light in first case in meter\n",
-      "lambda2 = 7.e-7 # wavelength of light in second case in meter\n",
-      "\n",
-      "#Calculations\n",
-      "b_plus_d = (1/N)*10**-2\n",
-      "n1 = b_plus_d /  lambda1 # calculation for Observed order in first case\n",
-      "n2 = b_plus_d / lambda2 # calculation for Observed order in second case\n",
-      "\n",
-      "#Result\n",
-      "print \"Observed order = %.2f,%.2f\"%(n1,n2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Observed order = 6.25,3.57\n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.36, Page 2.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "N = 4000 # no. of lines in grating per meter\n",
-      "l = 5e-5 # wavelength of incident radiation in cm\n",
-      "n = 3 # no. of order\n",
-      "\n",
-      "#Calculation\n",
-      "p = (n * N) / (sqrt(1 - (N * n * l)))# dispersive power (p) = d(theta)/d(lambda)\n",
-      "\n",
-      "#Result\n",
-      "print \"Dispersive power = %.3e rad/m\"%p"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Dispersive power = 1.897e+04 rad/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.37, Page 2.52"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 2 # no. of order\n",
-      "lambda1 = 5.89e-7 # wavelength of light in first case in meter\n",
-      "lambda2 = 5.896e-7 # wavelength of light in second case in meter\n",
-      "\n",
-      "#Calculation\n",
-      "N = lambda1 / (n * (lambda2 - lambda1)) # calculation for minimum no. of lines in grating \n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum no. of lines in grating = %.1f\"%N"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum no. of lines in grating = 490.8\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.38, Page 2.53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "n = 1 # no. of order\n",
-      "lambda1 = 5.89e-7 # wavelength of light in first case in meter\n",
-      "lambda2 = 5.896e-7 # wavelength of light in second case in meter\n",
-      "\n",
-      "#Calculation\n",
-      "N = lambda1 / (n * (lambda2 - lambda1)) # calculation for minimum no. of lines in grating\n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum no. of lines in grating = %.2f\"%N"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum no. of lines in grating = 981.67\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.39, Page 2.53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi,sin\n",
-      "\n",
-      "# Given \n",
-      "n = 3 # no. of order\n",
-      "theta = pi / 6 # view angle of third order in radian\n",
-      "lambda1 = 5.89e-7 # min. wavelength of light in meter\n",
-      "lambda2 = 5.896e-7 # max.wavelength of light in meter\n",
-      "\n",
-      "#Calculations\n",
-      "mean_lambda = (lambda1 + lambda2) / 2 # calculation for mean wavelength\n",
-      "s = (n * mean_lambda) / sin(theta) # calculation for grating space b+d\n",
-      "N = lambda1 / (n * (lambda2 - lambda1)) # calculation for minimum no. of lines in grating\n",
-      "\n",
-      "#Result\n",
-      "print \"Grating space = %.3e meter. \\nTotal width of ruled surface = %.3e meter. \"%(s,s * N)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Grating space = 3.536e-06 meter. \n",
-        "Total width of ruled surface = 1.157e-03 meter. \n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.40, Page 2.53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "a = 5 # diameter of objective lens of telescope in meter\n",
-      "R = 3.8e8 # distance of moon in meter\n",
-      "\n",
-      "#Calculations\n",
-      "theta = (1.22 * l) / a # calculation for angle \n",
-      "x = (R * theta) # calculation for the separation of two points on moon\n",
-      "\n",
-      "#Result\n",
-      "print \"The separation of two points on moon = %.3f meter\"%x"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The separation of two points on moon = 50.996 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 35
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.41, Page 2.54"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "theta = (1e-3) * (pi / 180) # separation angle of stars in radian\n",
-      "\n",
-      "#Calculation\n",
-      "a = (1.22 * l) / theta # calculation for diameter of telescope objective\n",
-      "\n",
-      "#Result\n",
-      "print \"Diameter of telescope objective = %.5f meter\"%a"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of telescope objective = 0.03495 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.42, Page 42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 6e-7 # wavelength of light in meter\n",
-      "theta = 2.44e-6 # separation angle of stars in radian\n",
-      "\n",
-      "#Calculation\n",
-      "a = (1.22 * l) / theta # calculation for diameter of telescope objective\n",
-      "\n",
-      "#Result\n",
-      "print \"Diameter of telescope objective = %.2f meter\"%a"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of telescope objective = 0.30 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.43, Page 2.54"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "a = 0.004 # diameter of objective lens of telescope in meter\n",
-      "x = 1.5e-3 # distance between two pin holes in meter\n",
-      "\n",
-      "#Calculations\n",
-      "theta = (1.22 * l) / a # calculation for angle  \n",
-      "R = x / theta # calculation for max. distance of pin holes from microscope\n",
-      "\n",
-      "#Result\n",
-      "print \"Max. distance of pin holes from microscope = %.4f meter\"%R"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Max. distance of pin holes from microscope = 8.9419 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.44, Page 2.55"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sin\n",
-      "\n",
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "theta = pi / 6 # semi-angle of cone in radian\n",
-      "\n",
-      "#Calculation\n",
-      "d = (1.22 * l) / (2 * sin(theta)) # calculation for the resolving limit of microscope \n",
-      "\n",
-      "#Result\n",
-      "print \"The resolving limit of microscope = %.1e meter\"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The resolving limit of microscope = 6.7e-07 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 40
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2.45, Page 2.55"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.461e-7 # wavelength of light in meter\n",
-      "d = 4e-7 # separation between objects in meter\n",
-      "\n",
-      "#Calculation\n",
-      "NA = (1.22 * l) / (2 * d) # calculation for numerical aperture of objective \n",
-      "\n",
-      "#Result\n",
-      "print \"Numerical aperture of objective = %.3f\"%NA"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Numerical aperture of objective = 0.833\n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_20.ipynb b/Engineering_Physics/Chapter_20.ipynb
deleted file mode 100755
index 6252eb1b..00000000
--- a/Engineering_Physics/Chapter_20.ipynb
+++ /dev/null
@@ -1,755 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 20: X-Ray"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.1, Page 20.7"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "V1 = 40e3 # voltage in first case in V\n",
-      "V2 = 20e3 # voltage in second case in V\n",
-      "V3 = 100e3 # voltage in second in V\n",
-      "\n",
-      "#Calculations\n",
-      "v1 = 0.593e6 * sqrt(V1)\n",
-      "lambda1 = 12400 / V1\n",
-      "v2 = 0.593e6 * sqrt(V2)\n",
-      "lambda2 = 12400 / V2\n",
-      "v3 = 0.593e6 * sqrt(V3)\n",
-      "lambda3 = 12400 / V3\n",
-      "\n",
-      "#Results\n",
-      "print \"Max. speed of electrons at %d Volts is %.3e m/sec\\nMax. speed of electrons at %d Volts is %.2e m/sec/sec\\nMax. speed of electrons at %d Volts is %.3e m/sec\\nShortest wavelength of x-ray = %.2f A\\nShortest wavelength of x-ray = %.2f A\\nShortest wavelength of x-ray = %.3f A\"%(V1,v1,V2,v2,V3,v3,lambda1,lambda2,lambda3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Max. speed of electrons at 40000 Volts is 1.186e+08 m/sec\n",
-        "Max. speed of electrons at 20000 Volts is 8.39e+07 m/sec/sec\n",
-        "Max. speed of electrons at 100000 Volts is 1.875e+08 m/sec\n",
-        "Shortest wavelength of x-ray = 0.31 A\n",
-        "Shortest wavelength of x-ray = 0.62 A\n",
-        "Shortest wavelength of x-ray = 0.124 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.2, Page 20.7\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "V = 30e3 # voltage in V\n",
-      "lambda_min = 0.414e-10 # shortest wavelength in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "h = (e * V * lambda_min) / c\n",
-      "\n",
-      "#Result\n",
-      "print \"Planck constant is %.3e J sec\"%h"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Planck constant is 6.624e-34 J sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.3, Page 20.8"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "V = 25e3 # voltage in V\n",
-      "\n",
-      "#Calculations\n",
-      "lambda_min = 12400 / V\n",
-      "\n",
-      "#Result\n",
-      "print \"Minimum wavelength of x-ray is %.3f A\"%lambda_min"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Minimum wavelength of x-ray is 0.496 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.4, Page 20.8"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "V = 13.6e3 # voltage in V\n",
-      "\n",
-      "#Calculations\n",
-      "v = 0.593e6*sqrt(V)\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum speed of electron is %.2e m/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum speed of electron is 6.92e+07 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.5, Page 20.8"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "V = 10e3 # voltage in V\n",
-      "i = 2e-3 # current in amp\n",
-      "\n",
-      "#Calculations\n",
-      "v = 0.593e6*sqrt(V)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity of electron is %.2e m/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of electron is 5.93e+07 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.6, Page 20.8"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given\n",
-      "V = 9.8e3 # voltage in V\n",
-      "i = 2e-3 # current in amp\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 12400 / V\n",
-      "f = c / (lamda*10**-10)\n",
-      "\n",
-      "#Results\n",
-      "print \"Highest frequency is %.2e Hz\\nMinimum wavelength is %.2f A\"%(f,lamda)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Highest frequency is 2.37e+18 Hz\n",
-        "Minimum wavelength is 1.27 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.7, Page 20.9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import *\n",
-      "\n",
-      "# Given \n",
-      "V = 12.4e3 # voltage in V\n",
-      "i = 2e-3 # current in amp\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "n = i / e\n",
-      "v = 0.593e6*sqrt(V)\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of electrons striking the target per sec is %.2e\\nSpeed of electrons is %.1e m/sec\"%(n,v)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of electrons striking the target per sec is 1.25e+16\n",
-        "Speed of electrons is 6.6e+07 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.8, Page 20.9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "V = 10e3 # voltage in V\n",
-      "i = 15e-3 # current in amp\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "n = i / e\n",
-      "lamda = 12400 / V \n",
-      "\n",
-      "#Results\n",
-      "print \"Number of electrons striking the anode per sec is %.2e\\nMinimum wavelength produced  is %.2f A\"%(n,lamda)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of electrons striking the anode per sec is 9.38e+16\n",
-        "Minimum wavelength produced  is 1.24 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.9, Page 20.9"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "V = 50e3 # voltage in V\n",
-      "i = 1e-3 # current in amp\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "\n",
-      "#Calculations\n",
-      "n = i / e\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of electrons striking the anode per sec is %.2e\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of electrons striking the anode per sec is 6.25e+15\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.10, Page 20.10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lambda1 = 40e-12 # minimum wavelength in first case in m\n",
-      "lambda2 = 1e-10 # minimum wavelength in second case in m\n",
-      "\n",
-      "#Calculations\n",
-      "V1 = 12400e-10 / lambda1\n",
-      "V2 = 12400e-10 / lambda2\n",
-      "\n",
-      "#Results\n",
-      "print \"Applied voltage to get wavelength of %.e meter is %.f KV\\nApplied voltage to get wavelength of %.e meter is %.1f KV\"%(lambda1,V1/10**3,lambda2,V2/10**3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Applied voltage to get wavelength of 4e-11 meter is 31 KV\n",
-        "Applied voltage to get wavelength of 1e-10 meter is 12.4 KV\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.11, Page 20.10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "V1 = 44e3 # voltage in first case in V\n",
-      "V2 = 50e3 # voltage in second case in V\n",
-      "lambda1 = 0.284e-10 # shortest wavelength in first case in m\n",
-      "lambda2 = 0.248e-10 # shortest wavelength in second case in m\n",
-      "e = 1.6e-19 # charge on an electron in C\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "h1 = e * V1 * lambda1 / c\n",
-      "h2 = e * V2 * lambda2 / c\n",
-      "\n",
-      "#Results\n",
-      "print \"Planck constant is %.2e J sec if shortest wavelength is %.3e m \\nPlanck constant is %.3e Jsec if shortest wavelength is %.3e m \"%(h1,lambda1,h2,lambda2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Planck constant is 6.66e-34 J sec if shortest wavelength is 2.840e-11 m \n",
-        "Planck constant is 6.613e-34 Jsec if shortest wavelength is 2.480e-11 m \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.12, Page 20.10"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 1e-11 # K-absorption limit for uranium in m\n",
-      "\n",
-      "#Calculations\n",
-      "V = 12400e-10 / lamda\n",
-      "\n",
-      "#Result\n",
-      "print \"Excitation potential is %d kV\"%(V/10**3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Excitation potential is 124 kV\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.13, Page 20.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "lamda = 1.4e-11 # K-absorption edge for lead in m\n",
-      "V = 88.6e3 # minimum voltage required for producing k-lines in V\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "r = V * lamda / c\n",
-      "\n",
-      "#Result\n",
-      "print \"The value of the ratio of h/e = %.3e Jsec/C\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The value of the ratio of h/e = 4.135e-15 Jsec/C\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.14, Page 20.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 92 # atomic no. of atom\n",
-      "Rh = 1.1e5 # Rydberg constant in cm^-1\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "lamda = 1 / (Rh *(Z-1)**2 * (1 - (1 / 2**2)))\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of K line = %.2f A\"%(lamda*1e8)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of K line = 0.11 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.15, Page 20.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 42 # atomic no. of Mo\n",
-      "lamda = 0.71e-10 # wavelength in m\n",
-      "Z_ = 29 # atomic no. of Cu\n",
-      "\n",
-      "#Calculations\n",
-      "lambda_ = (Z-1)**2 * lamda / (Z_-1)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of the corresponding radiation of Cu is %.2f A\"%(lambda_*1e10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of the corresponding radiation of Cu is 1.52 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.16, Page 20.12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 79 # atomic no. of element\n",
-      "b = 1 # a constant\n",
-      "a = 2.468e15 # a constant in per sec\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "f = a * (Z - b)**2\n",
-      "lamda = c / f\n",
-      "\n",
-      "#Result\n",
-      "print \"Wavelength of x-ray is %.4f A\"%(lamda*1e10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength of x-ray is 0.1998 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.17, Page 20.12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 29 # atomic no. of Cu\n",
-      "R = 1.097e7 # Rydberg constant in m^-1\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "\n",
-      "#Calculations\n",
-      "f = 3./4 * (R * c) * (Z-1)**2\n",
-      "E = h * f / 1.6e-16\n",
-      "E_L = 0.931 # let E_L = 0.931 KeV\n",
-      "E_ = E + E_L\n",
-      "\n",
-      "#Result\n",
-      "print \"Ionization potential of K-shell electron of Cu is %.3f keV\"%E_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ionization potential of K-shell electron of Cu is 8.938 keV\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.18, Page 20.13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 79 # atomic no. of anticathode\n",
-      "R = 1.097e7 # Rydberg constant in m^-1\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "\n",
-      "#Calculations\n",
-      "f = 3./4 * (R * c) * (Z-1)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Frequency of k line is %.3e Hz\"%f"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency of k line is 1.502e+19 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20.19, Page 20.13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "Z = 27 # atomic no. of Co\n",
-      "R = 1.097e7 # Rydberg constant in m^-1\n",
-      "c = 3e8 # speed of light in m/sec\n",
-      "h = 6.62e-34 # Planck constant in J sec\n",
-      "\n",
-      "#Calculations\n",
-      "f = 3./4 * (R * c) * (Z-1)**2\n",
-      "E = h * f\n",
-      "lamda = c / f\n",
-      "\n",
-      "#Results\n",
-      "print \"Energy is %.2f keV\\nWavelength of x-ray is %.2f A\"%(E / 1.6e-16,lamda*1e10)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy is 6.90 keV\n",
-        "Wavelength of x-ray is 1.80 A\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_22.ipynb b/Engineering_Physics/Chapter_22.ipynb
deleted file mode 100755
index a955c292..00000000
--- a/Engineering_Physics/Chapter_22.ipynb
+++ /dev/null
@@ -1,62 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 22: Nanopyhsics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 22.1, Page 22.13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "\n",
-      "# Given \n",
-      "d = 12e-6 # diameter in m\n",
-      "d_ = 90e-9 # diameter of nanoparticle in m\n",
-      "\n",
-      "#Calculations\n",
-      "r = d / 2\n",
-      "r_ = d_ / 2\n",
-      "k = r / 3\n",
-      "k_ = r_ / 3\n",
-      "R = k_ / k\n",
-      "\n",
-      "#Result\n",
-      "print \"The ratio of the value of Nb/Ns of spherical particle and nanoparticle = %.1e\"%R"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The ratio of the value of Nb/Ns of spherical particle and nanoparticle = 7.5e-03\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_3.ipynb b/Engineering_Physics/Chapter_3.ipynb
deleted file mode 100755
index 1e5fdb51..00000000
--- a/Engineering_Physics/Chapter_3.ipynb
+++ /dev/null
@@ -1,996 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3: Polarisation"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.1, Page 3.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, atan\n",
-      "\n",
-      "# Given \n",
-      "mu = 1.5 # refractive index of glass\n",
-      "\n",
-      "#Calculations\n",
-      "Ip = atan(mu) * (180 / pi) # by brewster's law\n",
-      "r = 90 - Ip # calculation for angle of refraction\n",
-      "\n",
-      "#Result\n",
-      "print \"Brewster angle = %.f degree\\nAngle of refraction = %.f degree\"%(Ip,r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Brewster angle = 56 degree\n",
-        "Angle of refraction = 34 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.2, Page 3.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, atan\n",
-      "\n",
-      "# Given \n",
-      "mu = 1.33 # refractive index of glass\n",
-      "\n",
-      "#Calculations\n",
-      "Ip = atan(mu) * (180 / pi) # by Brewster's law\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle of brewster = %.2f degree\"%Ip"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of brewster = 53.06 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.3, Page 3.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, atan\n",
-      "\n",
-      "# Given \n",
-      "mu_w = 1.33 # refractive index of water\n",
-      "mu_g = 1.54 # refractive index of glass\n",
-      "\n",
-      "#Calculations\n",
-      "Ip_1 = atan(mu_g / mu_w) * (180 / pi)#calculation for polarizing angle for water\n",
-      "Ip_2 = atan(mu_w / mu_g) * (180 / pi) # calculation for polarizing angle for glass\n",
-      "\n",
-      "#Result\n",
-      "print \"Polarizing angle for water to glass = %.2f degree,\\n Polarizing angle for glass to water = %.2f degree\"%(Ip_1,Ip_2)\n",
-      "print \"So polarizing angle is greater for a beam incident from water to glass\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Polarizing angle for water to glass = 49.18 degree,\n",
-        " Polarizing angle for glass to water = 40.82 degree\n",
-        "So polarizing angle is greater for a beam incident from water to glass\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.4, Page 24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, asin, tan, sin\n",
-      "\n",
-      "# Given \n",
-      "Ip = pi / 3 # polarizing angle of piece of glass for green light in radian\n",
-      "a = pi / 3 # angle of prism in radian \n",
-      "\n",
-      "#Calculations\n",
-      "mu = tan(Ip) # calculation for refractive index\n",
-      "delta_m = 2 * (asin(mu * sin(a / 2)) - (a / 2)) * (180 / pi) # calculation for angle of minimum deviation\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle of minimum deviation = %.f degree\"%delta_m"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of minimum deviation = 60 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 47
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.5, Page 3.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, atan\n",
-      "\n",
-      "# Given \n",
-      "mu_w = 1.33 # refractive index of water\n",
-      "mu_g = 1.5 # refractive index of glass\n",
-      "\n",
-      "#Calculations\n",
-      "Ip = atan(mu_g / mu_w) * (180 / pi) # calculation for Brewster angle\n",
-      "\n",
-      "#Result\n",
-      "print \"Brewster angle = %.1f degree\"%Ip\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Brewster angle = 48.4 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.6, Page 3.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, atan\n",
-      "\n",
-      "# Given \n",
-      "mu = 1.732 # refractive index of glass\n",
-      "\n",
-      "#Calculations\n",
-      "Ip = atan(mu) * (180 / pi) # by Brewster's law\n",
-      "r = 90 - Ip# calculation for angle of refraction\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle of incidence = %.f degree\\nAngle of refraction = %.f degree\"%(Ip,r)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle of incidence = 60 degree\n",
-        "Angle of refraction = 30 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.7, Page 3.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, cos\n",
-      "\n",
-      "# Given \n",
-      "alpha = pi / 3 # angle between polarizer and analyzer\n",
-      "\n",
-      "#Calculation\n",
-      "r = (cos(alpha))**2 # where r = transmitted intensity / incident intensity\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio between transmitted intensity to incident intensity = %.2f \"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio between transmitted intensity to incident intensity = 0.25 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.8, Page 3.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt,acos,degrees\n",
-      "\n",
-      "#Given \n",
-      "r1 = 1./3  #ratio of intensity of transmitted light to the intensity of transmitted beam in first case\n",
-      "r2 = 1./3  #ratio of intensity of transmitted light to the intensity of incident beam in second case\n",
-      "p = 50    #percentage reduction in intensity of unpolarized light by the sheet \n",
-      "\n",
-      "#Calculations\n",
-      "theta1 = degrees(acos(sqrt(r1)))   #calculation for the angle between characteristics directions of the sheet in first case\n",
-      "theta2 = degrees(acos(sqrt(2*r2))) #calculation for the angle between characteristics directions of the sheet in second case\n",
-      "\n",
-      "#Result\n",
-      "print \"The angle between characteristics directions of the sheet in 1st case = %.2f degrees.\"%(theta1)\n",
-      "print \"The angle between characteristics directions of the sheet in 2nd case = %.2f degrees.\"%(theta2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The angle between characteristics directions of the sheet in 1st case = 54.74 degrees.\n",
-        "The angle between characteristics directions of the sheet in 2nd case = 35.26 degrees.\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.9, Page 3.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import acos, sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "r = 3. / 4 # ratio of intensity of transmitted light to the intensity of incident light\n",
-      "\n",
-      "#Calculation\n",
-      "theta = acos(sqrt(r)) * (180 / pi) # calculation for angle between the nicol prisms\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle between the nicol prisms = %.f degree\"%theta"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle between the nicol prisms = 30 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 45
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.10, Page 3.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, cos\n",
-      "\n",
-      "# Given \n",
-      "theta1 = pi / 6 # angle between Nicole prisms in first case in radian\n",
-      "theta2 = pi / 4 # angle between Nicole prisms in second case in radian\n",
-      "theta3 = pi / 3 # angle between Nicole prisms in third case in radian\n",
-      "theta4 = pi / 2 # angle between Nicole prisms in fourth case in radian\n",
-      "\n",
-      "#Calculations\n",
-      "I1 = (1 - (cos(theta1))**2) * 100\n",
-      "I2 = (1 - (cos(theta2))**2) * 100\n",
-      "I3 = (1 - (cos(theta3))**2) * 100\n",
-      "I4 = (1 - (cos(theta4))**2) * 100\n",
-      "\n",
-      "#Result\n",
-      "print \"Percentage reduction in intensity of light-\\n(i)%.f %%\\n(ii)%.f %%\\n(iii)%.f %%\\n(iv)%.f %%\"%(I1,I2,I3,I4)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Percentage reduction in intensity of light-\n",
-        "(i)25 %\n",
-        "(ii)50 %\n",
-        "(iii)75 %\n",
-        "(iv)100 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.11, Page 3.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, acos, sqrt \n",
-      "\n",
-      "# Given \n",
-      "i1 = 1. / 2 # reduced intensity ratio in first case\n",
-      "i2 = 1. / 4 # reduced intensity ratio in second case\n",
-      "\n",
-      "#Calculations\n",
-      "theta1 = acos(sqrt(i1)) * (180 / pi)# calculation for angle between nicols in first case \n",
-      "theta2 = acos(sqrt(i2)) * (180 / pi)# calculation for angle between nicols in second case\n",
-      "\n",
-      "#Result\n",
-      "print \"Angle between the Nicols in first case = %.f degree\\nAnd in second case = %.f degree\"%(theta1,theta2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angle between the Nicols in first case = 45 degree\n",
-        "And in second case = 60 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.12, Page 3.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "mu_e = 1.553 # refractive index for extraordinary light\n",
-      "mu_o = 1.544 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculations\n",
-      "t = l / (2 * (mu_e - mu_o)) # calculation for thickness of half-wave plate of quartz\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of half-wave plate of quartz = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of half-wave plate of quartz = 2.78e-05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.13, Page 3.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.893e-7 # wavelength of light in meter\n",
-      "mu_e = 1.533 # refractive index for extraordinary light\n",
-      "mu_o = 1.554 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (4 * (mu_o - mu_e)) # calculation for thickness of quartz plate\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of quartz plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of quartz plate  = 7.02e-06 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.14, Page 3.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "mu_e1 = 1.5 # refractive index for extraordinary light in first case\n",
-      "mu_o1 = 1.55 # refractive index for ordinary light in first case\n",
-      "mu_e2 = 1.57 # refractive index for extraordinary light in second case\n",
-      "mu_o2 = 1.55 # refractive index for ordinary light in second case\n",
-      "\n",
-      "#Calculations\n",
-      "t1 = l / (4 * (mu_o1 - mu_e1))\n",
-      "t2 = l / (4 * (mu_e2 - mu_o2))\n",
-      " # calculation for thickness of plate of quartz\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of plate of quartz in first case = %.3e meter,\\nAnd thickness of plate of quartz in second case = %.2e meter\"%(t1,t2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of plate of quartz in first case = 2.945e-06 meter,\n",
-        "And thickness of plate of quartz in second case = 7.36e-06 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.15, Page 3.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "mu_e = 1.486 # refractive index for extraordinary light\n",
-      "mu_o = 1.658 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (4 * (mu_o - mu_e)) # calculation for thickness of calcite plate \n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of calcite plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of calcite plate  = 8.56e-07 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.16, Page 3.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5e-7 # wavelength of light in meter\n",
-      "mu_e = 1.5533 # refractive index for extraordinary light\n",
-      "mu_o = 1.5442 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (4 * (mu_e - mu_o)) # calculation for thickness of quartz plate\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of quartz plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of quartz plate  = 1.37e-05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.17, Page 3.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "mu_e = 1.54 # refractive index for extraordinary light\n",
-      "mu_o = 1.55 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (4 * (mu_o - mu_e)) # calculation for thickness of quartz plate\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of quartz plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of quartz plate  = 1.47e-05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.18, Page 3.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "l = 5.89e-7 # wavelength of light in meter\n",
-      "mu_e = 1.553 # refractive index for extraordinary light\n",
-      "mu_o = 1.544 # refractive index for ordinary light\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (4 * (mu_e - mu_o)) # calculation for thickness of quartz plate\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of quartz plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of quartz plate  = 1.64e-05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.19, Page 3.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "mu_e = 1.5442 # refractive index for extraordinary light\n",
-      "mu_o = 1.5533 # refractive index for ordinary light\n",
-      "l = 5e-7 # wavelength of plane polarized light in meter\n",
-      "\n",
-      "#Calculation\n",
-      "t = l / (2 * (mu_o - mu_e))# calculation for thickness of quartz plate\n",
-      "\n",
-      "#Result\n",
-      "print \"Thickness of quartz plate  = %.2e meter\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Thickness of quartz plate  = 2.75e-05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 27
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.20, Page 3.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 10 # rotation of plane of polarization in degree\n",
-      "s = 60 # specific rotation of sugar solution in degree per decimeter per unit concentration\n",
-      "l = 2.5 # length of Polari meter in decimeter\n",
-      "\n",
-      "#Calculation\n",
-      "c = theta / (s * l) # calculation for concentration of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Concentration of sugar solution = %.3f gm/cc\"%c"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Concentration of sugar solution = 0.067 gm/cc\n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.21, Page 3.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 26.4 # rotation of plane of polarization in degree\n",
-      "c = 0.2 # concentration of sugar solution in gm/cc\n",
-      "l = 2 # length of polarizing tube in decimeter\n",
-      "\n",
-      "#Calculation\n",
-      "s = theta / (l * c)# calculation for specific rotation of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Specific rotation of sugar solution = %.f degree/(dm-cc)\"%s"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Specific rotation of sugar solution = 66 degree/(dm-cc)\n"
-       ]
-      }
-     ],
-     "prompt_number": 43
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.22, Page 3.29"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 6.5 # rotation of plane of polarization in degree\n",
-      "c = 0.05 # concentration of sugar solution in gm/cc\n",
-      "l = 2 # length of polarizing tube in decimeter\n",
-      "\n",
-      "#Calculation\n",
-      "s = theta / (l * c) # calculation for specific rotation of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Specific rotation of sugar solution = %.f degree/(dm-cc)\"%s"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Specific rotation of sugar solution = 65 degree/(dm-cc)\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.23, Page 3.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "w = 80 # weight of impure sugar in gm\n",
-      "theta = 9.9 # rotation of plane of polarization in degree\n",
-      "s = 66 # specific rotation of sugar solution in degree per decimeter per unit concentration\n",
-      "l = 2 # length of Polari meter in decimeter\n",
-      "\n",
-      "#Calculations\n",
-      "c = theta / (s * l) * (1000) # in gm/l\n",
-      "per_c = (c * 100) / w # calculation for concentration of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Concentration of sugar solution = %.2f percent\"%per_c"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Concentration of sugar solution = 93.75 percent\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.24, Page 3.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 11. # rotation of plane of polarization in degree\n",
-      "s = 66 # specific rotation of sugar solution in degree per decimeter per unit concentration\n",
-      "l = 2 # length of Polari meter in decimeter\n",
-      "\n",
-      "#Calculation\n",
-      "c = theta / (s * l) # calculation for concentration of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Concentration of sugar solution = %.4f gm/cc\"%c"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Concentration of sugar solution = 0.0833 gm/cc\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.25, Page 3.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 26.4 # rotation of plane of polarization in degree\n",
-      "c = 0.2 # concentration of sugar solution in gm/cc\n",
-      "l = 2 # length of polarizing tube in decimeter\n",
-      "\n",
-      "#calculation\n",
-      "s = theta / (l * c) # calculation for specific rotation of sugar solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Specific rotation of sugar solution = %.f degree/(dm-cc)\"%s"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Specific rotation of sugar solution = 66 degree/(dm-cc)\n"
-       ]
-      }
-     ],
-     "prompt_number": 40
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3.26, Page 3.30"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "theta = 13 # rotation of plane of polarization in degree\n",
-      "r = (1. / 3) # ratio of the final concentration to the initial solution\n",
-      "l = 2 # length of Polari meter in decimeter\n",
-      "l_ = 3 # length of second polarizing tube in decimeter \n",
-      "\n",
-      "#Calculation\n",
-      "theta_ = (l_ * r * theta) / l# calculation for optical rotation of diluted solution\n",
-      "\n",
-      "#Result\n",
-      "print \"Optical rotation of diluted solution = %.1f degree\"%theta_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Optical rotation of diluted solution = 6.5 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_4.ipynb b/Engineering_Physics/Chapter_4.ipynb
deleted file mode 100755
index 981a3d82..00000000
--- a/Engineering_Physics/Chapter_4.ipynb
+++ /dev/null
@@ -1,311 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Lasers and Holography"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.1, Page 4.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import exp\n",
-      "\n",
-      "# Given \n",
-      "l = 5.5e-7 # wavelength of light in meter\n",
-      "c = 3e+8 # speed of light in m/sec\n",
-      "h = 6.63e-34 # Planck constant in j/sec\n",
-      "e = 1.6e-19 # charge on electron in coulomb \n",
-      "k = 8.62e-5 # Boltzmann constant in eV/K\n",
-      "T = 300 # temperature in kelvin\n",
-      "\n",
-      "#Calculations\n",
-      "delta_E = (h * c) / (l * e) # calculation for energy difference \n",
-      "r = exp(-delta_E / (k * T)) # calculation for ratio of population of upper level to the lower energy level\n",
-      "T_ = (delta_E / (k * 0.693)) # calculation for temperature for the second condition\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of population of upper level to the lower energy level = %.1e. \\nTemperature for the second condition = %.f K. \"%(r,T_)\n",
-      "#Incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of population of upper level to the lower energy level = 1.1e-38. \n",
-        "Temperature for the second condition = 37837 K. \n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.2, Page 4.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "lambda1 = 6.328e-7 # wavelength of light in first case in meter\n",
-      "lambda2 =2e-7 # wavelength of light in second case in meter\n",
-      "r1 = 2.3e-4 # the radius of internal beam of laser in first case in meter\n",
-      "r2 = 2.4e-3 # the radius of internal beam of laser in second case in meter\n",
-      "\n",
-      "#Calculations\n",
-      "theta1 = lambda1 / (pi * r1) # calculation for beam divergence angle in first case\n",
-      "theta2 = lambda2 / (pi * r2) # calculation for beam divergence angle in second case\n",
-      "\n",
-      "#Result\n",
-      "print \"Beam divergence angle in first case = %.2e radian. \\nBeam divergence angle in second case = %.2e radian. \"%(theta1,theta2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Beam divergence angle in first case = 8.76e-04 radian. \n",
-        "Beam divergence angle in second case = 2.65e-05 radian. \n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.3, Page 4.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi,ceil\n",
-      "\n",
-      "# Given \n",
-      "l = 6.0*10**-2 # length of laser in meter\n",
-      "D = 1.0*10**-2 # diameter of laser in meter\n",
-      "L = 6.944e-7 # wavelength of light in meter\n",
-      "d = 3700 # density of aluminium oxide in kg/meter cube\n",
-      "Na = 6e+23 # Avogadro number\n",
-      "M = 0.102 # molar mass of aluminium oxide in kg/meter cube\n",
-      "h = 4.1e-15 # Planck constant in eV-sec\n",
-      "c = 3e+8 # speed of light in meter/sec\n",
-      "\n",
-      "#Calculations\n",
-      "v = (pi * (D**2) * l) / 4 # calculation for volume \n",
-      "N = (2 * Na * d * v) / M # calculation for no. of aluminium ions\n",
-      "N_ = N / 3500 # calculation for the no. of chromium ions\n",
-      "E = (h * c) / L # calculation for the energy of stimulated emission photon \n",
-      "Et = N_ * E * (1.6e-19) # calculation for total energy\n",
-      "\n",
-      "#Result\n",
-      "print \"Total energy = %.f J\"%(ceil(Et))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Total energy = 17 J\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.4, Page 4.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "p = 4e-3 # energy of laser pulse in meter\n",
-      "r = 1.5e-5 # radius of spot in meter\n",
-      "t = 1e-9 # pulse length in time in sec\n",
-      "\n",
-      "#Calculations\n",
-      "p_ = p / t# calculation for  power in watt\n",
-      "I = p_ / (pi * r**2)# calculation for power per unit area delivered by the laser\n",
-      "\n",
-      "#Result\n",
-      "print \"Power per unit area delivered by the laser = %.1e watt/square meter\"%I"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Power per unit area delivered by the laser = 5.7e+15 watt/square meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.5, Page 4.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "D = 5e-3 # diameter of laser in meter\n",
-      "l = 7.2e-7 # wavelength of light in meter\n",
-      "d = 4e8 # distance at moon from earth in meter\n",
-      "\n",
-      "#Calculations\n",
-      "r = (D / 2) # calculation for radius\n",
-      "theta = (0.637 * l) / r # calculation for angular spread\n",
-      "areal_spread = (d * theta)**2 # calculation for areal spread\n",
-      "\n",
-      "#Result\n",
-      "print \"Angular spread = %.3e radian ,\\nAreal spread = %.2e square meter\"%(theta,areal_spread)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Angular spread = 1.835e-04 radian ,\n",
-        "Areal spread = 5.38e+09 square meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.6, Page 4.27\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "D = 5.0e-3 # diameter of laser in meter\n",
-      "l = 6.943e-7 # wavelength of light in meter\n",
-      "f =0.1 # focal length in meter\n",
-      "P = 0.1 # power of laser in watt\n",
-      "\n",
-      "#Calculations\n",
-      "r = (D / 2)# calculation for \n",
-      "theta = (0.637 * l) / r# calculation for angular spread\n",
-      "areal_spread = (f * theta)**2# calculation for areal spread\n",
-      "I = P / areal_spread# calculation for intensity\n",
-      "\n",
-      "#Result\n",
-      "print \"Areal spread = %.3e square meter,\\nIntensity = %.3e watt/square meter\"%(areal_spread,I)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Areal spread = 3.130e-10 square meter,\n",
-        "Intensity = 3.195e+08 watt/square meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4.7, Page 4.28"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "tou = 1e-10 # coherence time in sec\n",
-      "l = 5.4e-7 # wavelength of light in meter\n",
-      "\n",
-      "#Calculations\n",
-      "delta_v = 1 / tou \n",
-      "v_ = (3e+8) / l # calculation for frequency\n",
-      "d = delta_v / v_ # calculation for degree of non-monochromaticity\n",
-      "\n",
-      "#Result\n",
-      "print \"Degree of non-monochromaticity = %f \"%d"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Degree of non-monochromaticity = 0.000018 \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_5.ipynb b/Engineering_Physics/Chapter_5.ipynb
deleted file mode 100755
index e9ebdd41..00000000
--- a/Engineering_Physics/Chapter_5.ipynb
+++ /dev/null
@@ -1,549 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5: Fibre Optics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.1, Page 5.15"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sqrt, asin\n",
-      "\n",
-      "# Given \n",
-      "mu1 = 1.52 # refractive index for core\n",
-      "mu2 = 1.41 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "theta_c = asin(mu2 / mu1) * (180 / pi)\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "theta_0 = asin(NA) * (180 / pi)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical angle = %.2f degree \\nNumerical aperture = %.3f\\nMaximum incidence angle = %.1f degree\"%(theta_c,NA,theta_0)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical angle = 68.07 degree \n",
-        "Numerical aperture = 0.568\n",
-        "Maximum incidence angle = 34.6 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.2, Page 5.16"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sqrt, asin\n",
-      "\n",
-      "# Given \n",
-      "mu1 = 1.6 # refractive index for core\n",
-      "mu2 = 1.5 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)#calculation for numerical aperture\n",
-      "theta_0 = asin(NA) * (180 / pi)#calculation for maximum incidence angle\n",
-      "\n",
-      "#Result\n",
-      "print \"Numerical aperture = %.3f\\nMaximum incidence angle = %.2f degree\"%(NA,theta_0)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Numerical aperture = 0.557\n",
-        "Maximum incidence angle = 33.83 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.3, Page 5.16"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sqrt, asin\n",
-      " \n",
-      "# Given \n",
-      "mu_0 = 1 # refractive index of air\n",
-      "mu1 = 1.5 # refractive index for core\n",
-      "mu2 = 1.48 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "theta_c = asin(mu2 / mu1) * (180 / pi)\n",
-      "delta_mu = (mu1 - mu2) / mu1\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "theta_0 = asin(NA) * (180 / pi)\n",
-      "\n",
-      "#Result\n",
-      "print \"Critical angle = %.2f degrees \\nNumerical aperture = %.3f \\nAcceptance angle = %.2f degrees\\nFractional refractive index = %.2f %%\"%(theta_c,NA,theta_0,delta_mu*100)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Critical angle = 80.63 degrees \n",
-        "Numerical aperture = 0.244 \n",
-        "Acceptance angle = 14.13 degrees\n",
-        "Fractional refractive index = 1.33 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.4, Page 5.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import * \n",
-      "# Given \n",
-      "mu1 = 1.62 # refractive index for core\n",
-      "mu2 = 1.52 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "theta_0 = asin(NA) * (180 / pi)\n",
-      "\n",
-      "#Results\n",
-      "print \"Numerical aperture = %.2f \\nMaximum incidence angle = %.1f degrees\"%(NA,theta_0)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Numerical aperture = 0.56 \n",
-        "Maximum incidence angle = 34.1 degrees\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.5, Page 5.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "NA = 0.22 # numerical aperture\n",
-      "delta_mu = 0.012 # fractional refractive index\n",
-      "\n",
-      "#Calculations\n",
-      "mu1 = sqrt(NA**2 / (1 - (1 - delta_mu)**2))\n",
-      "mu2 = (1 - delta_mu) * mu1\n",
-      "\n",
-      "#Result\n",
-      "print \"Refractive index for core = %.3f\\nRefractive index for cladding = %.2f\"%(mu1,mu2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Refractive index for core = 1.424\n",
-        "Refractive index for cladding = 1.41\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.6, Page 5.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sqrt, asin, sin\n",
-      "\n",
-      "# Given \n",
-      "d = 0.0064 # diameter of fiber in cm\n",
-      "mu1 = 1.53 # refractive index for core\n",
-      "mu2 = 1.39 # refractive index for clad\n",
-      "L = 90 # length of fiber in cm\n",
-      "mu_0 = 1 # refractive index of air\n",
-      "\n",
-      "#calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "theta_0 = asin(NA) * (180 / pi)\n",
-      "N1 = L / (d * sqrt((mu1 / (mu_0 * sin(theta_0 * (pi / 180))))**2 - 1))\n",
-      "N2 = L / (d * sqrt((mu1 / (mu_0 * sin(theta_0 * (pi / 360))))**2 - 1))\n",
-      "\n",
-      "#Result\n",
-      "print \"Numerical aperture = %.2f\\nAcceptance angle = %.1f degrees \\nNumber of reflections at maximum incidence = %.f \\nNumber of reflections in second case = %.f \"%(NA,theta_0,N1,N2)\n",
-      "#Incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Numerical aperture = 0.64\n",
-        "Acceptance angle = 39.7 degrees \n",
-        "Number of reflections at maximum incidence = 6468 \n",
-        "Number of reflections in second case = 3204 \n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.7, Page 5.18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "d = 0.05 # diameter of fiber in mm\n",
-      "NA = 0.22 # numerical aperture\n",
-      "l = 8.5e-4 # wavelength of light in mm\n",
-      "\n",
-      "#calculations\n",
-      "Vn = (pi * d * NA) / l\n",
-      "Mm = 0.5 * (Vn)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"The normalized frequency = %.2f\\nNumber of guided in the core = %d\"%(Vn,Mm)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The normalized frequency = 40.66\n",
-        "Number of guided in the core = 826\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.8, Page 5.18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 1.25e-6 #wavelength of light in meter\n",
-      "mu1 = 1.465 # refractive index for core\n",
-      "mu2 = 1.460 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "k = (2.4 * l) / ( pi * NA)\n",
-      "Mm = 0.5 * ((pi * 50e-6 * NA) / l)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Diameter of core < %.1e meter,\\n number of modes = %d\"%(k,Mm)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Diameter of core < 7.9e-06 meter,\n",
-        " number of modes = 115\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.9, Page 5.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 0.85e-6 #wavelength of light in meter\n",
-      "mu1 = 1.461 # refractive index for core\n",
-      "mu2 = 1.456 # refractive index for clad\n",
-      "d = 4e-5 # diameter of core in meter\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)\n",
-      "Mm = 0.5 * ((pi * d * NA) / l)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Numerical aperture = %.3f\\n Number of modes = %d \"%(NA,Mm)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Numerical aperture = 0.121\n",
-        " Number of modes = 159 \n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.10, Page 5.19\n"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given\n",
-      "mu1 = 3.6 # refractive index for core\n",
-      "mu2 = 3.55 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)#calculation for numerical aperture\n",
-      "Mm1 = 0.5 * (pi * 5 * NA)**2#calculation for no. of modes in first case\n",
-      "Mm2 = 0.5 * (pi * 50 * NA)**2#calculation for no. of modes in second case\n",
-      "\n",
-      "#Result\n",
-      "print \"Number of modes in first case = %d \\nNumber of modes in second case = %d\"%(Mm1,Mm2)\n",
-      "#Incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Number of modes in first case = 44 \n",
-        "Number of modes in second case = 4410\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.11, Page 5.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 1.25e-6 #wavelength of light in meter\n",
-      "mu1 = 1.46 # refractive index for core\n",
-      "mu2 = 1.457 # refractive index for cladding\n",
-      "\n",
-      "#Calculations\n",
-      "NA = sqrt(mu1**2 - mu2**2)#calculation for numerical aperture\n",
-      "k = (2.4 * l) / ( pi * NA)\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum diameter of core = %.2f micro meter\"%(k*1e6)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum diameter of core = 10.21 micro meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.12, Page 5.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import log10\n",
-      "\n",
-      "# Given \n",
-      "L = 0.1 # length of fiber in km\n",
-      "p = 5e-6 # power of signal in watt\n",
-      "p_ = 1e-6 # power of signal inside the fiber in watt\n",
-      "\n",
-      "#Calculation\n",
-      "alpha = (10 * log10(p / p_)) / L#calculation for absorption coefficient\n",
-      "\n",
-      "#Result\n",
-      "print \"Absorption coefficient = %d dB/km \"%alpha"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Absorption coefficient = 69 dB/km \n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5.13, Page 5.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import exp\n",
-      "\n",
-      "# Given \n",
-      "L = 3 # length of optical fiber in km\n",
-      "l = 6 # losses in dB\n",
-      "p = 5e-3 # input power in watt \n",
-      "\n",
-      "#calculations\n",
-      "alpha = (l * 3) / L\n",
-      "p_ = p / (exp((2.303 * alpha * L) / 10))\n",
-      "\n",
-      "#Result\n",
-      "print \"Output power = %.3f mW \"%(p_*1e3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Output power = 0.079 mW \n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_6.ipynb b/Engineering_Physics/Chapter_6.ipynb
deleted file mode 100755
index 76ec5aef..00000000
--- a/Engineering_Physics/Chapter_6.ipynb
+++ /dev/null
@@ -1,399 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Electron Optics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.1, Page 6.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "V = 500 # voltage across the electrode in eV\n",
-      "m = 9e-31 # mass of electron in kg\n",
-      "e = 1.6e-19 # charge on an electron in coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "E = e * V\n",
-      "v = sqrt((2 * e * V) / m)\n",
-      "p = m * v\n",
-      "\n",
-      "#Result\n",
-      "print \"Energy gained by electron = %.e J\\nSpeed of electron = %.2e meter/sec\\nMomentum of electron = %.2e kg-meter/sec\"%(E,v,p)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Energy gained by electron = 8e-17 J\n",
-        "Speed of electron = 1.33e+07 meter/sec\n",
-        "Momentum of electron = 1.20e-23 kg-meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.2, Page 6.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "v = 2.5e6 # speed of electron in meter/sec\n",
-      "B = 2e-4 # magnetic field in tesla\n",
-      "r = 1.76e11 # ratio of charge on electron to the mass of electron in C/kg\n",
-      "\n",
-      "#Calculations\n",
-      "a = (B * r * v)\n",
-      "\n",
-      "#Result\n",
-      "print \"Momentum of acceleration = %.2e meter/square sec.\"%a"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Momentum of acceleration = 8.80e+13 meter/square sec.\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.4, Page 6.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given that\n",
-      "v = 5.2e6 # speed of electron in meter/sec\n",
-      "B = 1.3e-4 # magnetic field in tesla\n",
-      "r = 1.76e11 # ratio of charge on electron to the mass of electron in C/kg\n",
-      "E = 3.2e-12 # energy of the electron beam in J\n",
-      "M = 9e-31 # mass of an electron in kg\n",
-      "\n",
-      "R = v / (r * B)\n",
-      "v_ = sqrt((2 * E) / M )\n",
-      "\n",
-      "print \"Radius of circle traced by the beam = %.1f cm. \\nSpeed of beam in second case = %.2e meter/sec\"%(R*100,v_)\n",
-      "print \"Speed of beam in second case is greater than speed of light so we cannot use above formula.\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Radius of circle traced by the beam = 22.7 cm. \n",
-        "Speed of beam in second case = 2.67e+09 meter/sec\n",
-        "Speed of beam in second case is greater than speed of light so we cannot use above formula.\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.5, Page 6.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "V = 2.500e3 # voltage across the electrode in V\n",
-      "E = 3.6e4 # strength of electric field in V/m\n",
-      "B = 1.2e-3 # magnetic field in tesla\n",
-      "\n",
-      "#Calculation\n",
-      "r = (E / B)**2 / (2 * V)#calculation for ratio of the charge on an electron to the mass of an electron\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of the charge on an electron to the mass of an electron = %.1e C/kg.\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of the charge on an electron to the mass of an electron = 1.8e+11 C/kg.\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.6, Page 6.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "M = 9.1e-31 # mass of electron in kg\n",
-      "E = 1.6e-15 # energy of electron in J\n",
-      "B = 5e-5 # magnetic field in tesla\n",
-      "e = 1.6e-19 # charge on an electron in coulomb\n",
-      "\n",
-      "#Calculations\n",
-      "v = sqrt((2 * E) / M)\n",
-      "r = (M * v) / (e * B)\n",
-      "\n",
-      "#Result\n",
-      "print \"Larmoure radius = %.2f meter\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Larmoure radius = 6.75 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.7, Page 6.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "Mp = 1.67e-27 # mass of proton in kg\n",
-      "v = 3e5 # speed of proton in meter/sec\n",
-      "B = 5e-9 # magnetic field in tesla\n",
-      "e = 1.6e-19 # charge on a proton in coulomb\n",
-      "\n",
-      "#Calculation\n",
-      "r = (Mp * v) / (e * B)#calculation for Larmour radius\n",
-      "\n",
-      "#Result\n",
-      "print \"Larmour radius = %.2e meter\"%r"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Larmour radius = 6.26e+05 meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.8, Page 6.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "M = 6.68e-27 # mass of helium ion in kg\n",
-      "E = 1.6e-16 # energy of helium ion in J\n",
-      "B = 5e-2 # magnetic field in tesla\n",
-      "e = 1.6e-19 # charge on helium ion in coulomb\n",
-      "\n",
-      "#calculations\n",
-      "v = sqrt((2 * E) / M)#calculation for velocity\n",
-      "r = (M * v) / (e * B)#calculation for Larmour radius\n",
-      "A = pi * r**2#calculation for area traced by the trajectory of helium ion\n",
-      "\n",
-      "#Result\n",
-      "print \"Area traced by the trajectory of helium ion = %.3f square meter\"%A"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Area traced by the trajectory of helium ion = 0.105 square meter\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.9, Page 6.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 100 # strength of electric field in V/m\n",
-      "B = 1e-3 # magnetic field in tesla\n",
-      "\n",
-      "#Calculation\n",
-      "v = E / B\n",
-      "\n",
-      "#Result\n",
-      "print \"The drift of the guiding center = %.e m/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The drift of the guiding center = 1e+05 m/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.10, Page 6.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "v = 1e6 # velocity of ion beam in m/sec\n",
-      "B = 1 # magnetic field in tesla\n",
-      "\n",
-      "#Calculation\n",
-      "E = B * v\n",
-      "\n",
-      "#Result\n",
-      "print \"Internal electric field = %.e V/m\"%E"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Internal electric field = 1e+06 V/m\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6.12, Page 6.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "r = 1.1 # ratio of new number of turns to the initial number of turns\n",
-      "\n",
-      "#Calculation\n",
-      "r_ = (1 / r)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of the new focus length to the initial focus length = %.3f \"%r_"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of the new focus length to the initial focus length = 0.826 \n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_7.ipynb b/Engineering_Physics/Chapter_7.ipynb
deleted file mode 100755
index 6762cbc5..00000000
--- a/Engineering_Physics/Chapter_7.ipynb
+++ /dev/null
@@ -1,569 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 7: Waves and Oscillations"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.1, Page 7.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sin, sqrt\n",
-      "\n",
-      "# Given \n",
-      "E = 1.024e-3 # total energy of particle in J\n",
-      "T = 2 * pi # time period of S.H.M. in sec\n",
-      "x = 0.08 * sqrt(2) # distance of partile in meter\n",
-      "t = pi / 4 # time in second\n",
-      "\n",
-      "#Calculations\n",
-      "A = x / sin((2 * pi * t) / T)\n",
-      "M = (E * T**2) / (2 * pi**2 * A**2)\n",
-      "\n",
-      "#Result\n",
-      "print \"Amplitude = %.2f meter\\nMass of particle = %.f g\"%(A,M/1e-3)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Amplitude = 0.16 meter\n",
-        "Mass of particle = 80 g\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.2, Page 7.22"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "A = 0.05 # amplitude in meter\n",
-      "T = 10 # time period of S.H.M. in sec\n",
-      "\n",
-      "#Calculations\n",
-      "v = (A * 2 * pi) / T\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum amplitude of velocity = %.4f meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum amplitude of velocity = 0.0314 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.3, Page 7.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, sqrt\n",
-      "\n",
-      "# Given \n",
-      "E = 9 # total energy of particle in J\n",
-      "U = 5 # potential energy in J\n",
-      "A = 1 # amplitude in meter\n",
-      "m = 2. # mass of harmonic oscillator in kg\n",
-      "\n",
-      "#Calculations\n",
-      "kE = E - U# calculation for kinetic energy\n",
-      "k = (2 * kE) / A**2# calculation for force constant\n",
-      "T = (2 * pi) * sqrt(m / k)# calculation for time period\n",
-      "\n",
-      "#Result\n",
-      "print \"Force constant = %.f J/m\\nTime period = %.2f sec\"%(k,T)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Force constant = 8 J/m\n",
-        "Time period = 3.14 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.4, Page 7.23"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import asin, sin, pi\n",
-      "\n",
-      "# Given \n",
-      "A = 0.06 # amplitude in meter\n",
-      "T = 6 # time period of S.H.M. in sec\n",
-      "x = 0.03 # position of particle in meter\n",
-      "\n",
-      "#Calculations\n",
-      "delta = asin(1) # by the formula x=Asin(wt+delta) and (at t = 0,x=A) \n",
-      "t = x / (A * sin(((2 * pi) / T) + delta))\n",
-      "\n",
-      "#Result\n",
-      "print \"Time taken by the particle = %.f sec\"%t"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time taken by the particle = 1 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.5, Page 7.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "A = 0.05# amplitude in meter\n",
-      "T = 10 * pi # time period of s.h.m. in sec\n",
-      "\n",
-      "#Calculations\n",
-      "v = A * (2 * pi / T)\n",
-      "a = A * (2 * pi / T)**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum velocity = %.e meter/sec\\nacceleration = %.e m/sec^2\"%(v,a)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum velocity = 1e-02 meter/sec\n",
-        "acceleration = 2e-03 m/sec^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.6, Page 7.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi\n",
-      "\n",
-      "# Given \n",
-      "A = 0.06# amplitude in meter\n",
-      "T = 10 * pi # time period of s.h.m. in sec\n",
-      "\n",
-      "#Calculation\n",
-      "v = A * (2 * pi / T)\n",
-      "\n",
-      "#Result\n",
-      "print \"Maximum velocity = %.1e meter/sec\"%v"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Maximum velocity = 1.2e-02 meter/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.7, Page 7.24"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "k = 16 # stiffness constant of spring n/m\n",
-      "m = 1 # mass of particle in kg\n",
-      "\n",
-      "#Calculations\n",
-      "n = sqrt(k / m) / (2 * pi)\n",
-      "\n",
-      "#Result\n",
-      "print \"natural frequency = %.2f Hz\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "natural frequency = 0.64 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.8, Page 7.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "l = 1 # length of pendulum in meter\n",
-      "m = 2 # mass of particle in kg\n",
-      "g = 9.8 # acceleration due to gravity in m/sec^2\n",
-      "\n",
-      "#Calculation\n",
-      "T = 2 * pi * sqrt(l / g)\n",
-      "\n",
-      "#Result\n",
-      "print \"The time period of pendulum = %.f sec\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The time period of pendulum = 2 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.9, Page 7.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "m = 100. # mass of particle in gm\n",
-      "\n",
-      "#Calculation\n",
-      "n = (1 / (2 * pi)) * sqrt(10 / m) # by using given formula \n",
-      "\n",
-      "#Result\n",
-      "print \"Frequency  = %.2f Hz\"%n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Frequency  = 0.05 Hz\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.10, Page 7.25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "f = 3 # acceleration of pendulum in m/sec^2\n",
-      "l = 1 # length of pendulum in meter\n",
-      "g = 9.8 # acceleration due to gravity in m/sec^2\n",
-      "\n",
-      "#calculatiom\n",
-      "T = 2 * pi * sqrt(l / (g + f))\n",
-      "\n",
-      "#Result\n",
-      "print \"Time period of pendulum = %.2f sec\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time period of pendulum = 1.76 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.11, Page 7.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "x = 0.3 # stretch in spring in meter\n",
-      "m1 = 6 # mass of first body in kg\n",
-      "m2 = 1 # mass of second body in kg\n",
-      "g = 9.8 #  gravitational acceleration of earth in m/sec^2\n",
-      "\n",
-      "#Calculations\n",
-      "k = (m1 * g) / x\n",
-      "T = (2 * pi) * sqrt(m2 / k)\n",
-      "\n",
-      "#Result\n",
-      "print \"Time period of motion = %.2f sec \"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time period of motion = 0.45 sec \n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.12, Page 7.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt, pi\n",
-      "\n",
-      "# Given \n",
-      "x = 0.1 # compression in spring in m\n",
-      "F = 10 # restoring force in N\n",
-      "m = 4 # mass of body in kg\n",
-      "g = 9.8 # acceleration due to gravity in m/sec^2\n",
-      "\n",
-      "#Calculations\n",
-      "k = F / x\n",
-      "F_ = m * g\n",
-      "x_ = F_ / k\n",
-      "T = (2 * pi) * sqrt(m / k)\n",
-      "\n",
-      "#Result\n",
-      "print \"Time period of motion = %.2f sec \\nCompression of the spring due to the weight of the body = %.3f m \"%(T,x_)\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time period of motion = 1.26 sec \n",
-        "Compression of the spring due to the weight of the body = 0.392 m \n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.13, Page 7.26"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import exp\n",
-      "\n",
-      "# Given \n",
-      "t = 50. # relaxation time in sec\n",
-      "r = 1 / exp(1) # falls in amplitude and energy\n",
-      "\n",
-      "#Calculations\n",
-      "s = 1 / (2 * t)\n",
-      "T = 1 / s # by using formula A=A_exp(-st) and using r=A/A_\n",
-      "\n",
-      "#Result\n",
-      "print \"Time = %.f sec\"%T\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time = 100 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7.14, Page 7.27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import pi, exp\n",
-      "\n",
-      "# Given \n",
-      "n = 260 # frequency in Hz\n",
-      "Q = 2000 # quality factor\n",
-      "r = 1 / (exp(1)**2) # decrease in amplitude \n",
-      "\n",
-      "#Calculations\n",
-      "tou = Q / (2 * pi * n)\n",
-      "t = 2 * tou # by using formula A=A_exp(-st) and using r=A/A_\n",
-      "\n",
-      "#Result\n",
-      "print \"Time = %.3f sec\"%t\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Time = 2.449 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_8.ipynb b/Engineering_Physics/Chapter_8.ipynb
deleted file mode 100755
index 60f3ed3a..00000000
--- a/Engineering_Physics/Chapter_8.ipynb
+++ /dev/null
@@ -1,413 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Sound Waves and Acoustics of Buildings \n"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.1, Page 8.17"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "v = 34500 # speed of sound in cm/sec\n",
-      "f = 20 # lower limit of frequency for human hearing ear in Hz\n",
-      "f_ = 20000 # upper limit of frequency for human hearing ear in Hz\n",
-      "\n",
-      "#Clculations\n",
-      "l1 = v / f\n",
-      "l2 = v / f_\n",
-      "\n",
-      "#Results\n",
-      "print \"Wavelength range of the sound wave is %.f cm to %.f cm.\"%(l1,l2)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Wavelength range of the sound wave is 1725 cm to 1 cm.\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.2, Page 8.18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      "# Given \n",
-      "T = 373. # temperature in kelvin\n",
-      "d = 1.293e-3 # density of air at S.T.P. in gm/cm^3\n",
-      "d_ = 13.6 # density of mercury in gm/cm^3\n",
-      "Cp = 0.2417 # specific heat of air at constant pressure \n",
-      "Cv = 0.1715 # specific heat of air at constant volume\n",
-      "g = 980 # gravitational constant i dynes/cm^3\n",
-      "\n",
-      "#calculations\n",
-      "p = 76 * d_ * g\n",
-      "gama = Cp / Cv\n",
-      "v = sqrt(gama * (p / d))\n",
-      "v_ = v * sqrt(T / 273)\n",
-      "\n",
-      "#Result\n",
-      "print \"Velocity of sound in the air in %.f cm/sec.\"%v_\n",
-      "#Incorrect answer in textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Velocity of sound in the air in 38839 cm/sec.\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.3, Page 8.18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "from math import sqrt\n",
-      "\n",
-      " \n",
-      "# Given that\n",
-      "n = 512. # frequency of tuning fork in Hz \n",
-      "T = 290. # temperature in kelvin\n",
-      "l = 66.5 # wavelength of the gas emitted by tuning fork in cm\n",
-      "d = 1.293e-3 # density of air at S.T.P. in gm/cm^3\n",
-      "d_ = 13.6 # density of mercury in gm/cm^3\n",
-      "g = 980 # gravitational constant i dynes/cm^3\n",
-      "\n",
-      "#Calculations\n",
-      "p = 76 * d_ * g# calculation for pressure\n",
-      "v_ = n * l# calculation for velocity of sound in air at temperature 17 c \n",
-      "v = v_ * sqrt(273 / T)# calculation for velocity of sound in air at temp 0 c\n",
-      "gama = v**2 * (d / p)# calculation for ratio of two specific heat\n",
-      "\n",
-      "#Result\n",
-      "print \"Ratio of  two principal specific heats of air is %.2f\"%gama"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Ratio of  two principal specific heats of air is 1.39\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.4, Page 8.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "A = 15 * 30 # area of the floor in square meter\n",
-      "h = 6 # height of hall in meter\n",
-      "N = 500 # no. of people\n",
-      "t = 1.36 # optimum time for orchestral music in sec\n",
-      "k = 0.44 # absorption coefficient per person\n",
-      "\n",
-      "#Calculations\n",
-      "aS = 0.161 * ((A * h) / t)\n",
-      "a = N * k\n",
-      "a_ = aS - a\n",
-      "w = a_ + (N / 2) * k + (N / 2) * 0.02\n",
-      "t = (0.161 * (A * h)) / w\n",
-      "\n",
-      "#Results\n",
-      "print \"Coefficient of absorption to be provided by the walls, floor and ceiling when the hall is fully occupied is %.f SI unit.\"%a_\n",
-      "print \"Reverberation time if only half upholstered seats are occupied is %.2f sec.\"%t\n",
-      "#Answer varies due to rounding-off "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "319.632352941\n",
-        "Coefficient of absorption to be provided by the walls, floor and ceiling when the hall is fully occupied is 100 SI unit.\n",
-        "Reverberation time if only half upholstered seats are occupied is 2.03 sec.\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.5, Page 8.19"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given\n",
-      "V = 8000 # volume of hall in meter^3\n",
-      "t = 1.8 # reverberation time in sec\n",
-      "\n",
-      "#Calculation\n",
-      "aS = (0.161 * V) / t# calculation for the total absorption constant\n",
-      "\n",
-      "#Result\n",
-      "print \"The total absorption constant = %.3f O.W.U.\"%aS\n",
-      "#Incorrect answer in the textbook"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The total absorption constant = 715.556 O.W.U.\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.6, Page 8.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "V = 1700 # volume in meter^3\n",
-      "a1 = 98 # area of plastered wall in m^2\n",
-      "a2 = 144 # area of plastered ceiling in m^2\n",
-      "a3 = 15 # area of wooden door in m^2\n",
-      "a4 = 88 # area of cushioned chairs in m^2\n",
-      "a5 = 150 # area of audience (each person) in m^2\n",
-      "k1 = 0.03 # coefficient of absorption for plastered wall in O.W.U.\n",
-      "k2 = 0.04 # coefficient of absorption for plastered ceiling in O.W.U.\n",
-      "k3 = 0.06 # coefficient of absorption for wooden door in O.W.U.\n",
-      "k4 = 1 # coefficient of absorption for cushioned chair in O.W.U.\n",
-      "k5 = 4.7 # coefficient of absorption for audience (each person) in O.W.U.\n",
-      "\n",
-      "#Calculations\n",
-      "A1 = a1 * k1# calculation for the absorption by the plaster wall\n",
-      "A2 = a2 * k2# calculation for the absorption by the plastered ceiling\n",
-      "A3 = a3 * k3# calculation for wooden door\n",
-      "A4 = a4 * k4# calculation for cushioned chairs \n",
-      "A = A1 + A2 + A3 + A4# calculation for total absorption\n",
-      "T = 0.161 * (V / A)# calculation for reverberation time\n",
-      "\n",
-      "#Result\n",
-      "print \"Reverberation time is %.2f sec\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Reverberation time is 2.80 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.7, Page 8.20"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "V = 1400 # volume of hall in meter^3\n",
-      "C = 110 # seating capacity of hall \n",
-      "a1 = 98 # area of plastered wall in m^2\n",
-      "a2 = 144 # area of plastered ceiling in m^2\n",
-      "a3 = 15 # area of wooden door in m^2\n",
-      "a4 = 88 # area of cushioned chairs in m^2\n",
-      "a5 = 150 # area of audience (each person) in m^2\n",
-      "k1 = 0.03 # coefficient of absorption for plastered wall in O.W.U.\n",
-      "k2 = 0.04 # coefficient of absorption for plastered ceiling in O.W.U.\n",
-      "k3 = 0.06 # coefficient of absorption for wooden door in O.W.U.\n",
-      "k4 = 1 # coefficient of absorption for cushioned chair in O.W.U.\n",
-      "k5 = 4.7 # coefficient of absorption for audience (each person) in O.W.U.\n",
-      "\n",
-      "#Calculations\n",
-      "A1 = a1 * k1# calculation for the absorption by the plaster wall\n",
-      "A2 = a2 * k2# calculation for the absorption by the plastered ceiling\n",
-      "A3 = a3 * k3# calculation for wooden door\n",
-      "A4 = a4 * k4# calculation for cushioned chairs \n",
-      "A5 = C*k5 # the absorption due to persons\n",
-      "A = A1 + A2 + A3 + A4 + A5 # calculation for total absorption\n",
-      "T = (0.161 * V) / A# calculation for the reverberation time\n",
-      "\n",
-      "#Result\n",
-      "print \"Reverberation time is %.3f sec\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Reverberation time is 0.367 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.8, Page 8.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "V = 980 # volume in meter^3\n",
-      "a1 = 150 # area of wall in m^2\n",
-      "a2 = 95 # area of ceiling in m^2\n",
-      "a3 = 90 # area of floor in m^2\n",
-      "k1 = 0.03 # coefficient of absorption for wall in O.W.U.\n",
-      "k2 = 0.80 # coefficient of absorption for ceiling in O.W.U.\n",
-      "k3 = 0.06 # coefficient of absorption for floor in O.W.U.\n",
-      "\n",
-      "#calculations\n",
-      "A1 = a1 * k1\n",
-      "A2 = a2 * k2\n",
-      "A3 = a3 * k3\n",
-      "A = A1 + A2 + A3\n",
-      "T = 0.161 * (V / A)\n",
-      "\n",
-      "#Result\n",
-      "print \"Reverberation time = %.2f sec\"%T"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Reverberation time = 1.84 sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8.9, Page 8.21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "V = 980 # volume in meter^3\n",
-      "a = 1.58 # area of window in m^2\n",
-      "I_ = 1e-12 # standard intensity level of sound wave in W/m^2\n",
-      "l = 60 # intensity level in dB\n",
-      "\n",
-      "#calculations\n",
-      "I = I_ * 10**(l / 10)# calculation for intensity\n",
-      "AP = I * a# calculation for acoustic power\n",
-      "\n",
-      "#Result\n",
-      "print \"Acoustic power = %.2e watt\"%AP"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Acoustic power = 1.58e-06 watt\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/Chapter_9.ipynb b/Engineering_Physics/Chapter_9.ipynb
deleted file mode 100755
index a43c0fed..00000000
--- a/Engineering_Physics/Chapter_9.ipynb
+++ /dev/null
@@ -1,254 +0,0 @@
-{
- "metadata": {
-  "name": ""
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 9: Dielectrics"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.1, Page 9.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 10**6 # electric field inside the plates in V/m\n",
-      "d = 0.02 # distance between the plates in meter\n",
-      "k = 3 # dielectric constant of slab\n",
-      "e_ = 8.85e-12 # electric permittivity of air in C^2/Nm^2\n",
-      "\n",
-      "#Calculations\n",
-      "D = e_*k*E\n",
-      "P = D-e_*E\n",
-      "\n",
-      "#Result\n",
-      "print \"Polarization vector is %.2e C/m^2 \\nDisplacement vector is %.3e C/m^2\"%(P,D)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Polarization vector is 1.77e-05 C/m^2 \n",
-        "Displacement vector is 2.655e-05 C/m^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.2, Page 9.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      " \n",
-      "# Given \n",
-      "E1 = 3*10**5 # electric intensity when space between plates evacuated in V/m\n",
-      "E2 = 1*10**5 # electric intensity when space between plates is filled with dielectric in V/m\n",
-      "e_ = 8.85e-12 # electric permittivity of air in C^2/Nm^2\n",
-      "\n",
-      "#calculation\n",
-      "sigma = e_*(E1 - E2)\n",
-      "\n",
-      "#result\n",
-      "print \"The included charge density on the surface of the dielectric is %.2e C/m^2\"%sigma"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The included charge density on the surface of the dielectric is 1.77e-06 C/m^2\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.3, Page 9.11"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 1*10**5 # electric field strength inside the plates in V/m\n",
-      "d = 6. # distance between the plates in mm\n",
-      "k = 2.8 # dielectric constant of slab\n",
-      "e_ = 8.85e-12 # electric permittivity of air in C^2/Nm^2\n",
-      "\n",
-      "#Calculations\n",
-      "P = e_*(k-1)*E\n",
-      "D = e_*k*E\n",
-      "energy_density = 1./2 * k*e_*E**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Polarization vector is %.1e C/m^2 \\nDisplacement vector is %.1eC/m^2 \\nEnergy density is %.3f J/m^3\"%(P,D,energy_density )"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Polarization vector is 1.6e-06 C/m^2 \n",
-        "Displacement vector is 2.5e-06C/m^2 \n",
-        "Energy density is 0.124 J/m^3\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.4, Page 9.12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "D = 5e-4 # electric displacement vector in C/m^2\n",
-      "P = 4e-4 # electric polarization vector in C/m^2\n",
-      "v = 0.5 # volume of the slab in m^3\n",
-      "e_ = 8.85e-12 # electric permittivity of air in C^2/Nm^2\n",
-      "\n",
-      "#Calculations\n",
-      "E= (D-P)/ e_\n",
-      "k = D/(e_*E)\n",
-      "p = P*v\n",
-      "energy_density = 1./2 * k*e_*E**2\n",
-      "\n",
-      "#Result\n",
-      "print \"Value of relative permittivity is %d \\nTotal dipole moment of the slab is %.e C-m\"%(k,p) "
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Value of relative permittivity is 5 \n",
-        "Total dipole moment of the slab is 2e-04 C-m\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.5, Page .12"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given that\n",
-      "E = 3e4 # external field in V/m\n",
-      "k = 1.00074 # dielectric constant of gas at N.T.P.\n",
-      "e_ = 8.85e-12 # electric permittivity of air in C^2/Nm^2\n",
-      "\n",
-      "#Calculations\n",
-      "x = k-1\n",
-      "P = x*e_*E\n",
-      "N = 6.023e23/22.4e-3\n",
-      "p = P/N\n",
-      "\n",
-      "#Result\n",
-      "print \"Induce dipole moment of each is %.2e C-m\"%p"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Induce dipole moment of each is 7.31e-36 C-m\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9.6, Page .13"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Given \n",
-      "E = 3e4 # external field in V/m\n",
-      "k = 1.000041 # dielectric constant of gas at 0 degree centigrate\n",
-      "\n",
-      "#calculation\n",
-      "x = k-1\n",
-      "\n",
-      "#Result\n",
-      "print \"Electric susceptibility at 0 degree centigrate is %.1e\"%x"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Electric susceptibility at 0 degree centigrate is 4.1e-05\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
\ No newline at end of file
diff --git a/Engineering_Physics/README.txt b/Engineering_Physics/README.txt
deleted file mode 100755
index 85c741ca..00000000
--- a/Engineering_Physics/README.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Contributed By: Muktesh Chaudhary
-Course: be
-College/Institute/Organization: Anglo Eastern ship management india Pvt. Ltd
-Department/Designation: Electrical & Electronics Officer
-Book Title: Engineering Physics
-Author: H. K. Malik & A. Singh
-Publisher: Tata McGraw Hill, New Delhi
-Year of publication: 2010
-Isbn: 9780070671539
-Edition: 1st
\ No newline at end of file
diff --git a/Engineering_Physics/screenshots/Untitled1.png b/Engineering_Physics/screenshots/Untitled1.png
deleted file mode 100755
index 2584f5af..00000000
--- a/Engineering_Physics/screenshots/Untitled1.png
+++ /dev/null
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deleted file mode 100755
index 6c937ec4..00000000
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deleted file mode 100755
index 7461d551..00000000
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deleted file mode 100755
index a47a6ec9..00000000
--- a/Engineering_Physics/screenshots/Untitled2_1.png
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--- a/Engineering_Physics/screenshots/Untitled3.png
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deleted file mode 100755
index cdbc1a6f..00000000
--- a/Engineering_Physics/screenshots/Untitled3_1.png
+++ /dev/null
diff --git a/Engineering_Physics/screenshots/noofphotons.png b/Engineering_Physics/screenshots/noofphotons.png
deleted file mode 100755
index bb15b8cf..00000000
--- a/Engineering_Physics/screenshots/noofphotons.png
+++ /dev/null
diff --git a/Engineering_Physics/screenshots/ref_indices.png b/Engineering_Physics/screenshots/ref_indices.png
deleted file mode 100755
index 300447f7..00000000
--- a/Engineering_Physics/screenshots/ref_indices.png
+++ /dev/null
diff --git a/Engineering_Physics/screenshots/wavelenK.png b/Engineering_Physics/screenshots/wavelenK.png
deleted file mode 100755
index da79e117..00000000
--- a/Engineering_Physics/screenshots/wavelenK.png
+++ /dev/null