54 files changed, 15200 insertions, 0 deletions
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE AND DIFFRACTION OF LIGHT.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE AND DIFFRACTION OF LIGHT.ipynb
new file mode 100644
index 00000000..7c7516bf
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE AND DIFFRACTION OF LIGHT.ipynb
@@ -0,0 +1,630 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 1:INTERFERENCE AND DIFFRACTION OF LIGHT"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.1, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The fringe width beta= 0.2945 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "D=1                    #Distance in metre\n",
+    "lamda=589*10**-9       #nm to metres\n",
+    "d=2*10**-3             #mm to metre\n",
+    "\n",
+    "#Calculation\n",
+    "beta=(D*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"The fringe width beta=\",round(beta*10**3,4),\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.2, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness of glass plate= 3.27 micron.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=3               #position\n",
+    "lamda=5450*10**-10      #Wawelength in Armstrong to metre\n",
+    "mu=1.5\n",
+    "\n",
+    "#Calculation\n",
+    "t=(N*lamda)/(mu-1)\n",
+    "\n",
+    "#Result\n",
+    "print\"Thickness of glass plate=\",round(t*10**6,2),\"micron.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.3, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total number of lines n the grating= 9539.0\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "w=0.02      \n",
+    "n=1\n",
+    "lamda=6.56*10**-7\n",
+    "theta=(18+(14/60))*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "N=(w*math.sin(theta))/(n*lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"Total number of lines n the grating=\",round(N)\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.4, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "t= 11.786 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893*10**-10           #Angstroms to mts\n",
+    "x=4*10**-2\n",
+    "beta=1*10**-3\n",
+    "\n",
+    "#Calculation\n",
+    "t=(lamda*x)/(2*beta)\n",
+    "\n",
+    "#Result\n",
+    "print\"t=\",round(t*10**6,3),\"micron\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.6, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The minimum thickness of coating,t= 996.4 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5500\n",
+    "nf=1.38\n",
+    "\n",
+    "#Calculation\n",
+    "t=lamda/(4*nf)\n",
+    "\n",
+    "#Result\n",
+    "print\"The minimum thickness of coating,t=\",round(t,1),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.7, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelength,lamda= 5448.0 *10**-10 m\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "beta=0.00227     #distance between adjascent green lines\n",
+    "D=2.5             \n",
+    "d=0.0006        #distance between narrow slits\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(beta*d)/D\n",
+    "\n",
+    "#Result\n",
+    "print\"Wavelength,lamda=\",round(lamda*10**10),\"*10**-10 m\"\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.8, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest thickness of plate,t= 3927.0 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5890*10**-10\n",
+    "mu=1.5\n",
+    "theta=60*math.pi/180     #Converting in to degrees\n",
+    "\n",
+    "#Calculation\n",
+    "cos=math.cos(theta)\n",
+    "t=(lamda)/(2*mu*(math.cos(theta)))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Smallest thickness of plate,t=\",round(t*10**10),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.9, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index,mu = 1.31\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "R=1\n",
+    "n=5\n",
+    "lamda=5.895*10**-7\n",
+    "dn=0.003\n",
+    "\n",
+    "#Calculation\n",
+    "mu=(4*R*n*lamda)/(dn**2)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index,mu =\",mu "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.10, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 327.4\n",
+      "The number of rulings needed is 328. This is the minimum requirement.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893;\n",
+    "n=3\n",
+    "d_lamda=6\n",
+    "\n",
+    "#Calculation\n",
+    "N=(lamda)/(n*d_lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"N =\",round(N,1)\n",
+    "print\"The number of rulings needed is 328. This is the minimum requirement.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.11, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest angular separation of two stars = 2.642 *10**-7 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5.5*10**-7\n",
+    "d=2.54\n",
+    "x=1.22\n",
+    "#Calculation\n",
+    "dtheta=(x*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"Smallest angular separation of two stars =\",round(dtheta*10**7,3),\"*10**-7 radian\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 1.12, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Slit width value, a= 13000.0 Angstroms = 1.3 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6500\n",
+    "theta=30*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "a=lamda/math.sin(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Slit width value, a=\",a,\"Angstroms =\",round(a*10**-4,1),\"micron\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.13, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "r= 2.0 /1\n",
+      "Hence the ratio of the amplitudes= 2:1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a2=1\n",
+    "a1=2*a2\n",
+    "#Calculation\n",
+    "r=a1/a2\n",
+    "\n",
+    "#Result\n",
+    "print\"r=\",r,\"/1\"   #r = r/1 = r:1\n",
+    "print\"Hence the ratio of the amplitudes= 2:1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.14, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 73,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 2.0 *10**-4 m = 0.2 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=5*10**-3/2\n",
+    "lamda=5*10**-7\n",
+    "\n",
+    "#Calculation\n",
+    "a=(lamda)/theta\n",
+    "\n",
+    "print\"a=\",round(a*10**4),\"*10**-4 m\",\"=\",a*10**3,\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.15, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 76,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "mu-1= 0.4\n",
+      "Refractive index, mu= 1.4\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=20\n",
+    "lamda=5000*10**-10       #Angstroms to meters\n",
+    "t=2.5*10**-5\n",
+    "\n",
+    "#Calculation\n",
+    "mu_1=(N*lamda)/t\n",
+    "mu=1+(mu_1)\n",
+    "\n",
+    "#Result\n",
+    "print\"mu-1=\",mu_1\n",
+    "print\"Refractive index, mu=\",mu"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.16, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 79,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Maximum number of orders= 3.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=90*math.pi/180    #theta=90 degrees to get maximum number of orders assume\n",
+    "lamda=5890*10**-10\n",
+    "aplusb=2*10**-6       #micro mts to mts \n",
+    "\n",
+    "#Calculation\n",
+    "n=(aplusb*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"Maximum number of orders=\",round(n)\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT.ipynb
new file mode 100644
index 00000000..7c7516bf
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT.ipynb
@@ -0,0 +1,630 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 1:INTERFERENCE AND DIFFRACTION OF LIGHT"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.1, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The fringe width beta= 0.2945 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "D=1                    #Distance in metre\n",
+    "lamda=589*10**-9       #nm to metres\n",
+    "d=2*10**-3             #mm to metre\n",
+    "\n",
+    "#Calculation\n",
+    "beta=(D*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"The fringe width beta=\",round(beta*10**3,4),\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.2, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness of glass plate= 3.27 micron.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=3               #position\n",
+    "lamda=5450*10**-10      #Wawelength in Armstrong to metre\n",
+    "mu=1.5\n",
+    "\n",
+    "#Calculation\n",
+    "t=(N*lamda)/(mu-1)\n",
+    "\n",
+    "#Result\n",
+    "print\"Thickness of glass plate=\",round(t*10**6,2),\"micron.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.3, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total number of lines n the grating= 9539.0\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "w=0.02      \n",
+    "n=1\n",
+    "lamda=6.56*10**-7\n",
+    "theta=(18+(14/60))*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "N=(w*math.sin(theta))/(n*lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"Total number of lines n the grating=\",round(N)\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.4, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "t= 11.786 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893*10**-10           #Angstroms to mts\n",
+    "x=4*10**-2\n",
+    "beta=1*10**-3\n",
+    "\n",
+    "#Calculation\n",
+    "t=(lamda*x)/(2*beta)\n",
+    "\n",
+    "#Result\n",
+    "print\"t=\",round(t*10**6,3),\"micron\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.6, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The minimum thickness of coating,t= 996.4 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5500\n",
+    "nf=1.38\n",
+    "\n",
+    "#Calculation\n",
+    "t=lamda/(4*nf)\n",
+    "\n",
+    "#Result\n",
+    "print\"The minimum thickness of coating,t=\",round(t,1),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.7, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelength,lamda= 5448.0 *10**-10 m\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "beta=0.00227     #distance between adjascent green lines\n",
+    "D=2.5             \n",
+    "d=0.0006        #distance between narrow slits\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(beta*d)/D\n",
+    "\n",
+    "#Result\n",
+    "print\"Wavelength,lamda=\",round(lamda*10**10),\"*10**-10 m\"\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.8, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest thickness of plate,t= 3927.0 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5890*10**-10\n",
+    "mu=1.5\n",
+    "theta=60*math.pi/180     #Converting in to degrees\n",
+    "\n",
+    "#Calculation\n",
+    "cos=math.cos(theta)\n",
+    "t=(lamda)/(2*mu*(math.cos(theta)))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Smallest thickness of plate,t=\",round(t*10**10),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.9, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index,mu = 1.31\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "R=1\n",
+    "n=5\n",
+    "lamda=5.895*10**-7\n",
+    "dn=0.003\n",
+    "\n",
+    "#Calculation\n",
+    "mu=(4*R*n*lamda)/(dn**2)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index,mu =\",mu "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.10, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 327.4\n",
+      "The number of rulings needed is 328. This is the minimum requirement.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893;\n",
+    "n=3\n",
+    "d_lamda=6\n",
+    "\n",
+    "#Calculation\n",
+    "N=(lamda)/(n*d_lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"N =\",round(N,1)\n",
+    "print\"The number of rulings needed is 328. This is the minimum requirement.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.11, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest angular separation of two stars = 2.642 *10**-7 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5.5*10**-7\n",
+    "d=2.54\n",
+    "x=1.22\n",
+    "#Calculation\n",
+    "dtheta=(x*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"Smallest angular separation of two stars =\",round(dtheta*10**7,3),\"*10**-7 radian\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 1.12, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Slit width value, a= 13000.0 Angstroms = 1.3 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6500\n",
+    "theta=30*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "a=lamda/math.sin(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Slit width value, a=\",a,\"Angstroms =\",round(a*10**-4,1),\"micron\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.13, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "r= 2.0 /1\n",
+      "Hence the ratio of the amplitudes= 2:1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a2=1\n",
+    "a1=2*a2\n",
+    "#Calculation\n",
+    "r=a1/a2\n",
+    "\n",
+    "#Result\n",
+    "print\"r=\",r,\"/1\"   #r = r/1 = r:1\n",
+    "print\"Hence the ratio of the amplitudes= 2:1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.14, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 73,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 2.0 *10**-4 m = 0.2 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=5*10**-3/2\n",
+    "lamda=5*10**-7\n",
+    "\n",
+    "#Calculation\n",
+    "a=(lamda)/theta\n",
+    "\n",
+    "print\"a=\",round(a*10**4),\"*10**-4 m\",\"=\",a*10**3,\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.15, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 76,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "mu-1= 0.4\n",
+      "Refractive index, mu= 1.4\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=20\n",
+    "lamda=5000*10**-10       #Angstroms to meters\n",
+    "t=2.5*10**-5\n",
+    "\n",
+    "#Calculation\n",
+    "mu_1=(N*lamda)/t\n",
+    "mu=1+(mu_1)\n",
+    "\n",
+    "#Result\n",
+    "print\"mu-1=\",mu_1\n",
+    "print\"Refractive index, mu=\",mu"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.16, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 79,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Maximum number of orders= 3.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=90*math.pi/180    #theta=90 degrees to get maximum number of orders assume\n",
+    "lamda=5890*10**-10\n",
+    "aplusb=2*10**-6       #micro mts to mts \n",
+    "\n",
+    "#Calculation\n",
+    "n=(aplusb*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"Maximum number of orders=\",round(n)\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT_1.ipynb
new file mode 100644
index 00000000..7c7516bf
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/1.INTERFERENCE_AND_DIFFRACTION_OF_LIGHT_1.ipynb
@@ -0,0 +1,630 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 1:INTERFERENCE AND DIFFRACTION OF LIGHT"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.1, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The fringe width beta= 0.2945 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "D=1                    #Distance in metre\n",
+    "lamda=589*10**-9       #nm to metres\n",
+    "d=2*10**-3             #mm to metre\n",
+    "\n",
+    "#Calculation\n",
+    "beta=(D*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"The fringe width beta=\",round(beta*10**3,4),\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.2, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness of glass plate= 3.27 micron.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=3               #position\n",
+    "lamda=5450*10**-10      #Wawelength in Armstrong to metre\n",
+    "mu=1.5\n",
+    "\n",
+    "#Calculation\n",
+    "t=(N*lamda)/(mu-1)\n",
+    "\n",
+    "#Result\n",
+    "print\"Thickness of glass plate=\",round(t*10**6,2),\"micron.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.3, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total number of lines n the grating= 9539.0\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "w=0.02      \n",
+    "n=1\n",
+    "lamda=6.56*10**-7\n",
+    "theta=(18+(14/60))*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "N=(w*math.sin(theta))/(n*lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"Total number of lines n the grating=\",round(N)\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.4, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "t= 11.786 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893*10**-10           #Angstroms to mts\n",
+    "x=4*10**-2\n",
+    "beta=1*10**-3\n",
+    "\n",
+    "#Calculation\n",
+    "t=(lamda*x)/(2*beta)\n",
+    "\n",
+    "#Result\n",
+    "print\"t=\",round(t*10**6,3),\"micron\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.6, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The minimum thickness of coating,t= 996.4 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5500\n",
+    "nf=1.38\n",
+    "\n",
+    "#Calculation\n",
+    "t=lamda/(4*nf)\n",
+    "\n",
+    "#Result\n",
+    "print\"The minimum thickness of coating,t=\",round(t,1),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.7, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelength,lamda= 5448.0 *10**-10 m\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "beta=0.00227     #distance between adjascent green lines\n",
+    "D=2.5             \n",
+    "d=0.0006        #distance between narrow slits\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(beta*d)/D\n",
+    "\n",
+    "#Result\n",
+    "print\"Wavelength,lamda=\",round(lamda*10**10),\"*10**-10 m\"\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.8, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest thickness of plate,t= 3927.0 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5890*10**-10\n",
+    "mu=1.5\n",
+    "theta=60*math.pi/180     #Converting in to degrees\n",
+    "\n",
+    "#Calculation\n",
+    "cos=math.cos(theta)\n",
+    "t=(lamda)/(2*mu*(math.cos(theta)))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Smallest thickness of plate,t=\",round(t*10**10),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.9, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index,mu = 1.31\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "R=1\n",
+    "n=5\n",
+    "lamda=5.895*10**-7\n",
+    "dn=0.003\n",
+    "\n",
+    "#Calculation\n",
+    "mu=(4*R*n*lamda)/(dn**2)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index,mu =\",mu "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.10, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 327.4\n",
+      "The number of rulings needed is 328. This is the minimum requirement.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893;\n",
+    "n=3\n",
+    "d_lamda=6\n",
+    "\n",
+    "#Calculation\n",
+    "N=(lamda)/(n*d_lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"N =\",round(N,1)\n",
+    "print\"The number of rulings needed is 328. This is the minimum requirement.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.11, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest angular separation of two stars = 2.642 *10**-7 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5.5*10**-7\n",
+    "d=2.54\n",
+    "x=1.22\n",
+    "#Calculation\n",
+    "dtheta=(x*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"Smallest angular separation of two stars =\",round(dtheta*10**7,3),\"*10**-7 radian\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 1.12, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Slit width value, a= 13000.0 Angstroms = 1.3 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6500\n",
+    "theta=30*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "a=lamda/math.sin(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Slit width value, a=\",a,\"Angstroms =\",round(a*10**-4,1),\"micron\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.13, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "r= 2.0 /1\n",
+      "Hence the ratio of the amplitudes= 2:1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a2=1\n",
+    "a1=2*a2\n",
+    "#Calculation\n",
+    "r=a1/a2\n",
+    "\n",
+    "#Result\n",
+    "print\"r=\",r,\"/1\"   #r = r/1 = r:1\n",
+    "print\"Hence the ratio of the amplitudes= 2:1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.14, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 73,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 2.0 *10**-4 m = 0.2 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=5*10**-3/2\n",
+    "lamda=5*10**-7\n",
+    "\n",
+    "#Calculation\n",
+    "a=(lamda)/theta\n",
+    "\n",
+    "print\"a=\",round(a*10**4),\"*10**-4 m\",\"=\",a*10**3,\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.15, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 76,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "mu-1= 0.4\n",
+      "Refractive index, mu= 1.4\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=20\n",
+    "lamda=5000*10**-10       #Angstroms to meters\n",
+    "t=2.5*10**-5\n",
+    "\n",
+    "#Calculation\n",
+    "mu_1=(N*lamda)/t\n",
+    "mu=1+(mu_1)\n",
+    "\n",
+    "#Result\n",
+    "print\"mu-1=\",mu_1\n",
+    "print\"Refractive index, mu=\",mu"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.16, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 79,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Maximum number of orders= 3.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=90*math.pi/180    #theta=90 degrees to get maximum number of orders assume\n",
+    "lamda=5890*10**-10\n",
+    "aplusb=2*10**-6       #micro mts to mts \n",
+    "\n",
+    "#Calculation\n",
+    "n=(aplusb*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"Maximum number of orders=\",round(n)\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION AND ULTRASONICS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION AND ULTRASONICS.ipynb
new file mode 100644
index 00000000..d548c39e
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION AND ULTRASONICS.ipynb
@@ -0,0 +1,426 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 2:POLARIZATION AND ULTRASONICS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.1, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "theta= 45.0 degrees\n",
+      "theta= 135.0 degrees\n",
+      "#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "I=1/2\n",
+    "\n",
+    "#Calculation\n",
+    "theta1=math.acos(1/math.sqrt(2))*(180/math.pi)\n",
+    "theta2=math.acos(-1/math.sqrt(2))*(180/math.pi)\n",
+    "#Result\n",
+    "print\"theta=\",theta1,\"degrees\"\n",
+    "print\"theta=\",theta2,\"degrees\"\n",
+    "print\"#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.2, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ip= 60.0 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Calculation\n",
+    "ip=math.atan(1.732)*(180/math.pi)\n",
+    "\n",
+    "#Result\n",
+    "print\"ip=\",round(ip),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.3, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "phi= 104.7 rad.\n",
+      "Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1*10**-3\n",
+    "lamda=6000*10**-10\n",
+    "nd=0.01                  #difference between the refractive indices(n1 - n2)\n",
+    "\n",
+    "#Calculation\n",
+    "phi=(2*math.pi*d*nd)/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"phi=\",round(phi,1),\"rad.\"\n",
+    "print\"Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.4, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness,t= 27.47 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5000*10**-10\n",
+    "mu_0=1.5533\n",
+    "mu_1=1.5442\n",
+    "\n",
+    "#Calculations\n",
+    "t=lamda/(2*(mu_0 - mu_1))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Thickness,t=\",round(t*10**6,2),\"micro m.\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.5, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Birefringence of the crystal delta/mu= 0.005\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6000*10**-10\n",
+    "t=0.003*10**-2\n",
+    "\n",
+    "#Calculations\n",
+    "delta_mu=lamda/(4*t)\n",
+    "\n",
+    "#Result\n",
+    "print\"Birefringence of the crystal delta/mu=\",delta_mu\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.6, Page number 2.34¶"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index of medium= 1.732\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=60*(math.pi/180)        #When the angle of refraction is 30degrees, angle of reflection will be 60degrees\n",
+    "\n",
+    "#Calculation\n",
+    "mu=math.tan(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index of medium=\",round(mu,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.7, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Ultrasonic wavelength,lamda s = 7.47 *10**-4 m\n",
+      "Velocity of ultrasonic waves in liquid = 1495.0 ms**-1\n",
+      "#Answer varies due to rounding of numbers\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "m=1\n",
+    "lamda_l=6000*10**-10\n",
+    "theta=0.046*(math.pi/180)\n",
+    "n=2*10**6\n",
+    "\n",
+    "#Calculation\n",
+    "lamda_s=(m*lamda_l)/(math.sin(theta))\n",
+    "v=n*lamda_s\n",
+    "\n",
+    "#Result\n",
+    "print\"Ultrasonic wavelength,lamda s =\",round(lamda_s*10**4,2),\"*10**-4 m\"\n",
+    "print\"Velocity of ultrasonic waves in liquid =\",round(v),\"ms**-1\"\n",
+    "print\"#Answer varies due to rounding of numbers\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 2.8, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Velocity of blood flow = 0.1001 m s**-1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "C=1500\n",
+    "Df=267\n",
+    "f=2*10**6\n",
+    "theta=0*math.pi/180          #degrees\n",
+    "\n",
+    "#Calculation\n",
+    "V=(C*Df)/(2*f*math.cos(theta))\n",
+    "\n",
+    "#Result\n",
+    "print\"Velocity of blood flow =\",round(V,4),\"m s**-1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.9, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fundamental frequency,f = 4.0 *10**6 Hz.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "t=0.7*10**-3\n",
+    "E=8.8*10**10\n",
+    "rho=2800\n",
+    "\n",
+    "#Calculation\n",
+    "f=(1/(2*t))*math.sqrt(E/rho)       #Fundamental frequency\n",
+    "\n",
+    "#Result\n",
+    "print\"Fundamental frequency,f =\",round(f*10**-6),\"*10**6 Hz.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.10, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The depth of the sea = 997.5 m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "v=1500\n",
+    "t=1.33\n",
+    "\n",
+    "#Calculation\n",
+    "d=(v*t)/2\n",
+    "\n",
+    "#Result\n",
+    "print\"The depth of the sea =\",d,\"m.\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS.ipynb
new file mode 100644
index 00000000..d548c39e
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS.ipynb
@@ -0,0 +1,426 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 2:POLARIZATION AND ULTRASONICS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.1, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "theta= 45.0 degrees\n",
+      "theta= 135.0 degrees\n",
+      "#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "I=1/2\n",
+    "\n",
+    "#Calculation\n",
+    "theta1=math.acos(1/math.sqrt(2))*(180/math.pi)\n",
+    "theta2=math.acos(-1/math.sqrt(2))*(180/math.pi)\n",
+    "#Result\n",
+    "print\"theta=\",theta1,\"degrees\"\n",
+    "print\"theta=\",theta2,\"degrees\"\n",
+    "print\"#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.2, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ip= 60.0 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Calculation\n",
+    "ip=math.atan(1.732)*(180/math.pi)\n",
+    "\n",
+    "#Result\n",
+    "print\"ip=\",round(ip),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.3, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "phi= 104.7 rad.\n",
+      "Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1*10**-3\n",
+    "lamda=6000*10**-10\n",
+    "nd=0.01                  #difference between the refractive indices(n1 - n2)\n",
+    "\n",
+    "#Calculation\n",
+    "phi=(2*math.pi*d*nd)/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"phi=\",round(phi,1),\"rad.\"\n",
+    "print\"Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.4, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness,t= 27.47 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5000*10**-10\n",
+    "mu_0=1.5533\n",
+    "mu_1=1.5442\n",
+    "\n",
+    "#Calculations\n",
+    "t=lamda/(2*(mu_0 - mu_1))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Thickness,t=\",round(t*10**6,2),\"micro m.\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.5, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Birefringence of the crystal delta/mu= 0.005\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6000*10**-10\n",
+    "t=0.003*10**-2\n",
+    "\n",
+    "#Calculations\n",
+    "delta_mu=lamda/(4*t)\n",
+    "\n",
+    "#Result\n",
+    "print\"Birefringence of the crystal delta/mu=\",delta_mu\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.6, Page number 2.34¶"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index of medium= 1.732\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=60*(math.pi/180)        #When the angle of refraction is 30degrees, angle of reflection will be 60degrees\n",
+    "\n",
+    "#Calculation\n",
+    "mu=math.tan(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index of medium=\",round(mu,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.7, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Ultrasonic wavelength,lamda s = 7.47 *10**-4 m\n",
+      "Velocity of ultrasonic waves in liquid = 1495.0 ms**-1\n",
+      "#Answer varies due to rounding of numbers\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "m=1\n",
+    "lamda_l=6000*10**-10\n",
+    "theta=0.046*(math.pi/180)\n",
+    "n=2*10**6\n",
+    "\n",
+    "#Calculation\n",
+    "lamda_s=(m*lamda_l)/(math.sin(theta))\n",
+    "v=n*lamda_s\n",
+    "\n",
+    "#Result\n",
+    "print\"Ultrasonic wavelength,lamda s =\",round(lamda_s*10**4,2),\"*10**-4 m\"\n",
+    "print\"Velocity of ultrasonic waves in liquid =\",round(v),\"ms**-1\"\n",
+    "print\"#Answer varies due to rounding of numbers\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 2.8, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Velocity of blood flow = 0.1001 m s**-1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "C=1500\n",
+    "Df=267\n",
+    "f=2*10**6\n",
+    "theta=0*math.pi/180          #degrees\n",
+    "\n",
+    "#Calculation\n",
+    "V=(C*Df)/(2*f*math.cos(theta))\n",
+    "\n",
+    "#Result\n",
+    "print\"Velocity of blood flow =\",round(V,4),\"m s**-1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.9, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fundamental frequency,f = 4.0 *10**6 Hz.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "t=0.7*10**-3\n",
+    "E=8.8*10**10\n",
+    "rho=2800\n",
+    "\n",
+    "#Calculation\n",
+    "f=(1/(2*t))*math.sqrt(E/rho)       #Fundamental frequency\n",
+    "\n",
+    "#Result\n",
+    "print\"Fundamental frequency,f =\",round(f*10**-6),\"*10**6 Hz.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.10, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The depth of the sea = 997.5 m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "v=1500\n",
+    "t=1.33\n",
+    "\n",
+    "#Calculation\n",
+    "d=(v*t)/2\n",
+    "\n",
+    "#Result\n",
+    "print\"The depth of the sea =\",d,\"m.\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS_1.ipynb
new file mode 100644
index 00000000..d548c39e
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/2.POLARIZATION_AND_ULTRASONICS_1.ipynb
@@ -0,0 +1,426 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 2:POLARIZATION AND ULTRASONICS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.1, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "theta= 45.0 degrees\n",
+      "theta= 135.0 degrees\n",
+      "#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "I=1/2\n",
+    "\n",
+    "#Calculation\n",
+    "theta1=math.acos(1/math.sqrt(2))*(180/math.pi)\n",
+    "theta2=math.acos(-1/math.sqrt(2))*(180/math.pi)\n",
+    "#Result\n",
+    "print\"theta=\",theta1,\"degrees\"\n",
+    "print\"theta=\",theta2,\"degrees\"\n",
+    "print\"#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.2, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ip= 60.0 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Calculation\n",
+    "ip=math.atan(1.732)*(180/math.pi)\n",
+    "\n",
+    "#Result\n",
+    "print\"ip=\",round(ip),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.3, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "phi= 104.7 rad.\n",
+      "Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1*10**-3\n",
+    "lamda=6000*10**-10\n",
+    "nd=0.01                  #difference between the refractive indices(n1 - n2)\n",
+    "\n",
+    "#Calculation\n",
+    "phi=(2*math.pi*d*nd)/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"phi=\",round(phi,1),\"rad.\"\n",
+    "print\"Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.4, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness,t= 27.47 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5000*10**-10\n",
+    "mu_0=1.5533\n",
+    "mu_1=1.5442\n",
+    "\n",
+    "#Calculations\n",
+    "t=lamda/(2*(mu_0 - mu_1))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Thickness,t=\",round(t*10**6,2),\"micro m.\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.5, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Birefringence of the crystal delta/mu= 0.005\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6000*10**-10\n",
+    "t=0.003*10**-2\n",
+    "\n",
+    "#Calculations\n",
+    "delta_mu=lamda/(4*t)\n",
+    "\n",
+    "#Result\n",
+    "print\"Birefringence of the crystal delta/mu=\",delta_mu\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.6, Page number 2.34¶"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index of medium= 1.732\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=60*(math.pi/180)        #When the angle of refraction is 30degrees, angle of reflection will be 60degrees\n",
+    "\n",
+    "#Calculation\n",
+    "mu=math.tan(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index of medium=\",round(mu,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.7, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Ultrasonic wavelength,lamda s = 7.47 *10**-4 m\n",
+      "Velocity of ultrasonic waves in liquid = 1495.0 ms**-1\n",
+      "#Answer varies due to rounding of numbers\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "m=1\n",
+    "lamda_l=6000*10**-10\n",
+    "theta=0.046*(math.pi/180)\n",
+    "n=2*10**6\n",
+    "\n",
+    "#Calculation\n",
+    "lamda_s=(m*lamda_l)/(math.sin(theta))\n",
+    "v=n*lamda_s\n",
+    "\n",
+    "#Result\n",
+    "print\"Ultrasonic wavelength,lamda s =\",round(lamda_s*10**4,2),\"*10**-4 m\"\n",
+    "print\"Velocity of ultrasonic waves in liquid =\",round(v),\"ms**-1\"\n",
+    "print\"#Answer varies due to rounding of numbers\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 2.8, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Velocity of blood flow = 0.1001 m s**-1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "C=1500\n",
+    "Df=267\n",
+    "f=2*10**6\n",
+    "theta=0*math.pi/180          #degrees\n",
+    "\n",
+    "#Calculation\n",
+    "V=(C*Df)/(2*f*math.cos(theta))\n",
+    "\n",
+    "#Result\n",
+    "print\"Velocity of blood flow =\",round(V,4),\"m s**-1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.9, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fundamental frequency,f = 4.0 *10**6 Hz.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "t=0.7*10**-3\n",
+    "E=8.8*10**10\n",
+    "rho=2800\n",
+    "\n",
+    "#Calculation\n",
+    "f=(1/(2*t))*math.sqrt(E/rho)       #Fundamental frequency\n",
+    "\n",
+    "#Result\n",
+    "print\"Fundamental frequency,f =\",round(f*10**-6),\"*10**6 Hz.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.10, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The depth of the sea = 997.5 m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "v=1500\n",
+    "t=1.33\n",
+    "\n",
+    "#Calculation\n",
+    "d=(v*t)/2\n",
+    "\n",
+    "#Result\n",
+    "print\"The depth of the sea =\",d,\"m.\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS AND SUPERCONDUCTIVITY.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS AND SUPERCONDUCTIVITY.ipynb
new file mode 100644
index 00000000..a665a220
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS AND SUPERCONDUCTIVITY.ipynb
@@ -0,0 +1,472 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#3: ACOUSTICS OF BUILDINGS AND SUPERCONDUCTIVITY"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.1, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Reverbration time = 3.9 s\n",
+      "Final Reverbration time = 1.95 s\n",
+      "Thus the reverbration time is reduced to one-half of its initial value\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=2265\n",
+    "A=92.9\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "\n",
+    "#Result\n",
+    "print\"Reverbration time =\",round(T,1),\"s\"\n",
+    "print\"Final Reverbration time =\",round(T2,2),\"s\"\n",
+    "print\"Thus the reverbration time is reduced to one-half of its initial value\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.2, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of the hall = 2160 m**3\n",
+      "Total absorption = 430.7 m**2\n",
+      "Reverbration time = 0.8 second\n",
+      "Answer given for the Reverbration time in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a1=450    #Area of plastered wall\n",
+    "a2=360    #Area of wooden floor and wooden doors\n",
+    "a3=24     #Area of Glass\n",
+    "a4=600    #Area of seats\n",
+    "a5=500    #Area of audience when they are in seats\n",
+    "c1=0.03   #Coefficient of absorption of plastered wall\n",
+    "c2=0.06   #Coefficient of absorption of wooden floor and wooden doors\n",
+    "c3=0.025   #Coefficient of absorption of Glass\n",
+    "c4=0.3    #Coefficient of absorption of seats\n",
+    "c5=0.43   #Coefficient of absorption of audience when they are in seats\n",
+    "l=12\n",
+    "b=30\n",
+    "h=6\n",
+    "\n",
+    "#Calculation\n",
+    "V=l*b*h        #volume of the hall\n",
+    "A=(a1*c1)+(a2*c2)+(a3*c3)+(a4*c4)+(a5*c5)  #Total absorption\n",
+    "T=(0.16*V)/A   #Reverbration time\n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of the hall =\",V,\"m**3\"\n",
+    "print\"Total absorption =\",A,\"m**2\"\n",
+    "print\"Reverbration time =\",round(T,1),\"second\"\n",
+    "print\"Answer given for the Reverbration time in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.3, Page number 3.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total absorpttion = 1000.0  m**2 of O.W.U.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "T=1.2\n",
+    "V=7500\n",
+    "\n",
+    "#Calculation\n",
+    "A=(0.16*V)/T\n",
+    "\n",
+    "#Result\n",
+    "print\"Total absorpttion =\",A,\" m**2 of O.W.U.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.4, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "T1 = 1.45 second\n",
+      "T2 = 0.73 second\n",
+      "Change in Reverbration time = 0.727 second\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=12*10**4\n",
+    "A=13200\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T1=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "Td=T1-T2\n",
+    "\n",
+    "#Result\n",
+    "print\"T1 =\",round(T1,2),\"second\"\n",
+    "print\"T2 =\",round(T2,2),\"second\"\n",
+    "print\"Change in Reverbration time =\",round(Td,3),\"second\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.6, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "critical field is 33.64 *10**3 ampere/m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=64*10**3;    #initial field(ampere/m)\n",
+    "T=5;    #temperature(K)\n",
+    "Tc=7.26;   #transition temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "H=H0*(1-(T/Tc)**2);     #critical field(ampere/m)\n",
+    "\n",
+    "#Result\n",
+    "print \"critical field is\",round(H/10**3,2),\"*10**3 ampere/m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.7, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency of generated microwaves= 483.0 *10**9 Hz\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19\n",
+    "V=1*10\n",
+    "h=6.625*10**-34\n",
+    "\n",
+    "#Calculations\n",
+    "v=(2*e*V**-3)/h \n",
+    "\n",
+    "#Result\n",
+    "print\"Frequency of generated microwaves=\",round(v/10**9),\"*10**9 Hz\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.8, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of electrons per unit volume = 3.7 *10**28/m**3\n",
+      "Effective mass of electron 'm*' = 17.3 *10*-31 kg\n",
+      "Penetration depth = 3.81011659367 Angstroms\n",
+      "#The answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=7300                  #density in (kg/m**3)\n",
+    "N=6.02*10**26           #Avagadro Number\n",
+    "A=118.7                 #Atomic Weight\n",
+    "E=1.9                 #Effective mass\n",
+    "e=1.6*10**-19\n",
+    "\n",
+    "#Calculations\n",
+    "n=(d*N)/A\n",
+    "m=E*9.1*10**-31\n",
+    "x=4*math.pi*10**-7*n*e**2\n",
+    "lamda_L=math.sqrt(m/x)\n",
+    "      \n",
+    "#Result\n",
+    "print \"Number of electrons per unit volume =\",round(n/10**28,1),\"*10**28/m**3\"\n",
+    "print\"Effective mass of electron 'm*' =\",round(m*10**31,1),\"*10*-31 kg\"\n",
+    "print\"Penetration depth =\",lamda_L*10**8,\"Angstroms\"\n",
+    "print\"#The answer given in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 3.9, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tc = 7.0969 K\n",
+      "lamda0= 39.0 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda_L1=39.6*10**-9\n",
+    "lamda_L2=173*10**-9\n",
+    "T1=7.1\n",
+    "T2=3\n",
+    "\n",
+    "#Calculations\n",
+    "x=(lamda_L1/lamda_L2)**2\n",
+    "Tc4=(T1**4)-((T2**4)*x)/(1-x)\n",
+    "Tc=(Tc4)**(1/4)\n",
+    "print\"Tc =\",round(Tc,4),\"K\"\n",
+    "print\"lamda0=\",round((math.sqrt(1-(T2/Tc)**4)*lamda_L1)*10**9),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.10, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hc = 4.2759 *10**4\n",
+      "Critical current density,Jc = 1.71 *10**8 ampere/metre**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=6.5*10**4           #(ampere/metre)\n",
+    "T=4.2                  #K\n",
+    "Tc=7.18                #K\n",
+    "r=0.5*10**-3\n",
+    "\n",
+    "#Calculations\n",
+    "Hc=H0*(1-(T/Tc)**2)\n",
+    "Ic=(2*math.pi*r)*Hc\n",
+    "A=math.pi*r**2\n",
+    "Jc=Ic/A                #Critical current density\n",
+    "\n",
+    "#Result\n",
+    "print\"Hc =\",round(Hc/10**4,4),\"*10**4\"\n",
+    "print \"Critical current density,Jc =\",round(Jc/10**8,2),\"*10**8 ampere/metre**2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.11, Page number 6.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "New critical temperature for mercury = 4.145 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "Tc1=4.185\n",
+    "M1=199.5\n",
+    "M2=203.4\n",
+    "\n",
+    "#Calculations\n",
+    "Tc2=Tc1*(M1/M2)**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print\"New critical temperature for mercury =\",round(Tc2,3),\"K\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY.ipynb
new file mode 100644
index 00000000..a665a220
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY.ipynb
@@ -0,0 +1,472 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#3: ACOUSTICS OF BUILDINGS AND SUPERCONDUCTIVITY"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.1, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Reverbration time = 3.9 s\n",
+      "Final Reverbration time = 1.95 s\n",
+      "Thus the reverbration time is reduced to one-half of its initial value\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=2265\n",
+    "A=92.9\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "\n",
+    "#Result\n",
+    "print\"Reverbration time =\",round(T,1),\"s\"\n",
+    "print\"Final Reverbration time =\",round(T2,2),\"s\"\n",
+    "print\"Thus the reverbration time is reduced to one-half of its initial value\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.2, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of the hall = 2160 m**3\n",
+      "Total absorption = 430.7 m**2\n",
+      "Reverbration time = 0.8 second\n",
+      "Answer given for the Reverbration time in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a1=450    #Area of plastered wall\n",
+    "a2=360    #Area of wooden floor and wooden doors\n",
+    "a3=24     #Area of Glass\n",
+    "a4=600    #Area of seats\n",
+    "a5=500    #Area of audience when they are in seats\n",
+    "c1=0.03   #Coefficient of absorption of plastered wall\n",
+    "c2=0.06   #Coefficient of absorption of wooden floor and wooden doors\n",
+    "c3=0.025   #Coefficient of absorption of Glass\n",
+    "c4=0.3    #Coefficient of absorption of seats\n",
+    "c5=0.43   #Coefficient of absorption of audience when they are in seats\n",
+    "l=12\n",
+    "b=30\n",
+    "h=6\n",
+    "\n",
+    "#Calculation\n",
+    "V=l*b*h        #volume of the hall\n",
+    "A=(a1*c1)+(a2*c2)+(a3*c3)+(a4*c4)+(a5*c5)  #Total absorption\n",
+    "T=(0.16*V)/A   #Reverbration time\n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of the hall =\",V,\"m**3\"\n",
+    "print\"Total absorption =\",A,\"m**2\"\n",
+    "print\"Reverbration time =\",round(T,1),\"second\"\n",
+    "print\"Answer given for the Reverbration time in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.3, Page number 3.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total absorpttion = 1000.0  m**2 of O.W.U.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "T=1.2\n",
+    "V=7500\n",
+    "\n",
+    "#Calculation\n",
+    "A=(0.16*V)/T\n",
+    "\n",
+    "#Result\n",
+    "print\"Total absorpttion =\",A,\" m**2 of O.W.U.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.4, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "T1 = 1.45 second\n",
+      "T2 = 0.73 second\n",
+      "Change in Reverbration time = 0.727 second\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=12*10**4\n",
+    "A=13200\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T1=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "Td=T1-T2\n",
+    "\n",
+    "#Result\n",
+    "print\"T1 =\",round(T1,2),\"second\"\n",
+    "print\"T2 =\",round(T2,2),\"second\"\n",
+    "print\"Change in Reverbration time =\",round(Td,3),\"second\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.6, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "critical field is 33.64 *10**3 ampere/m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=64*10**3;    #initial field(ampere/m)\n",
+    "T=5;    #temperature(K)\n",
+    "Tc=7.26;   #transition temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "H=H0*(1-(T/Tc)**2);     #critical field(ampere/m)\n",
+    "\n",
+    "#Result\n",
+    "print \"critical field is\",round(H/10**3,2),\"*10**3 ampere/m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.7, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency of generated microwaves= 483.0 *10**9 Hz\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19\n",
+    "V=1*10\n",
+    "h=6.625*10**-34\n",
+    "\n",
+    "#Calculations\n",
+    "v=(2*e*V**-3)/h \n",
+    "\n",
+    "#Result\n",
+    "print\"Frequency of generated microwaves=\",round(v/10**9),\"*10**9 Hz\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.8, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of electrons per unit volume = 3.7 *10**28/m**3\n",
+      "Effective mass of electron 'm*' = 17.3 *10*-31 kg\n",
+      "Penetration depth = 3.81011659367 Angstroms\n",
+      "#The answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=7300                  #density in (kg/m**3)\n",
+    "N=6.02*10**26           #Avagadro Number\n",
+    "A=118.7                 #Atomic Weight\n",
+    "E=1.9                 #Effective mass\n",
+    "e=1.6*10**-19\n",
+    "\n",
+    "#Calculations\n",
+    "n=(d*N)/A\n",
+    "m=E*9.1*10**-31\n",
+    "x=4*math.pi*10**-7*n*e**2\n",
+    "lamda_L=math.sqrt(m/x)\n",
+    "      \n",
+    "#Result\n",
+    "print \"Number of electrons per unit volume =\",round(n/10**28,1),\"*10**28/m**3\"\n",
+    "print\"Effective mass of electron 'm*' =\",round(m*10**31,1),\"*10*-31 kg\"\n",
+    "print\"Penetration depth =\",lamda_L*10**8,\"Angstroms\"\n",
+    "print\"#The answer given in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 3.9, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tc = 7.0969 K\n",
+      "lamda0= 39.0 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda_L1=39.6*10**-9\n",
+    "lamda_L2=173*10**-9\n",
+    "T1=7.1\n",
+    "T2=3\n",
+    "\n",
+    "#Calculations\n",
+    "x=(lamda_L1/lamda_L2)**2\n",
+    "Tc4=(T1**4)-((T2**4)*x)/(1-x)\n",
+    "Tc=(Tc4)**(1/4)\n",
+    "print\"Tc =\",round(Tc,4),\"K\"\n",
+    "print\"lamda0=\",round((math.sqrt(1-(T2/Tc)**4)*lamda_L1)*10**9),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.10, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hc = 4.2759 *10**4\n",
+      "Critical current density,Jc = 1.71 *10**8 ampere/metre**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=6.5*10**4           #(ampere/metre)\n",
+    "T=4.2                  #K\n",
+    "Tc=7.18                #K\n",
+    "r=0.5*10**-3\n",
+    "\n",
+    "#Calculations\n",
+    "Hc=H0*(1-(T/Tc)**2)\n",
+    "Ic=(2*math.pi*r)*Hc\n",
+    "A=math.pi*r**2\n",
+    "Jc=Ic/A                #Critical current density\n",
+    "\n",
+    "#Result\n",
+    "print\"Hc =\",round(Hc/10**4,4),\"*10**4\"\n",
+    "print \"Critical current density,Jc =\",round(Jc/10**8,2),\"*10**8 ampere/metre**2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.11, Page number 6.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "New critical temperature for mercury = 4.145 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "Tc1=4.185\n",
+    "M1=199.5\n",
+    "M2=203.4\n",
+    "\n",
+    "#Calculations\n",
+    "Tc2=Tc1*(M1/M2)**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print\"New critical temperature for mercury =\",round(Tc2,3),\"K\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY_1.ipynb
new file mode 100644
index 00000000..a665a220
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/3.ACOUSTICS_AND_SUPERCONDUCTIVITY_1.ipynb
@@ -0,0 +1,472 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#3: ACOUSTICS OF BUILDINGS AND SUPERCONDUCTIVITY"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.1, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Reverbration time = 3.9 s\n",
+      "Final Reverbration time = 1.95 s\n",
+      "Thus the reverbration time is reduced to one-half of its initial value\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=2265\n",
+    "A=92.9\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "\n",
+    "#Result\n",
+    "print\"Reverbration time =\",round(T,1),\"s\"\n",
+    "print\"Final Reverbration time =\",round(T2,2),\"s\"\n",
+    "print\"Thus the reverbration time is reduced to one-half of its initial value\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.2, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of the hall = 2160 m**3\n",
+      "Total absorption = 430.7 m**2\n",
+      "Reverbration time = 0.8 second\n",
+      "Answer given for the Reverbration time in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a1=450    #Area of plastered wall\n",
+    "a2=360    #Area of wooden floor and wooden doors\n",
+    "a3=24     #Area of Glass\n",
+    "a4=600    #Area of seats\n",
+    "a5=500    #Area of audience when they are in seats\n",
+    "c1=0.03   #Coefficient of absorption of plastered wall\n",
+    "c2=0.06   #Coefficient of absorption of wooden floor and wooden doors\n",
+    "c3=0.025   #Coefficient of absorption of Glass\n",
+    "c4=0.3    #Coefficient of absorption of seats\n",
+    "c5=0.43   #Coefficient of absorption of audience when they are in seats\n",
+    "l=12\n",
+    "b=30\n",
+    "h=6\n",
+    "\n",
+    "#Calculation\n",
+    "V=l*b*h        #volume of the hall\n",
+    "A=(a1*c1)+(a2*c2)+(a3*c3)+(a4*c4)+(a5*c5)  #Total absorption\n",
+    "T=(0.16*V)/A   #Reverbration time\n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of the hall =\",V,\"m**3\"\n",
+    "print\"Total absorption =\",A,\"m**2\"\n",
+    "print\"Reverbration time =\",round(T,1),\"second\"\n",
+    "print\"Answer given for the Reverbration time in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.3, Page number 3.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total absorpttion = 1000.0  m**2 of O.W.U.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "T=1.2\n",
+    "V=7500\n",
+    "\n",
+    "#Calculation\n",
+    "A=(0.16*V)/T\n",
+    "\n",
+    "#Result\n",
+    "print\"Total absorpttion =\",A,\" m**2 of O.W.U.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.4, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "T1 = 1.45 second\n",
+      "T2 = 0.73 second\n",
+      "Change in Reverbration time = 0.727 second\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=12*10**4\n",
+    "A=13200\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T1=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "Td=T1-T2\n",
+    "\n",
+    "#Result\n",
+    "print\"T1 =\",round(T1,2),\"second\"\n",
+    "print\"T2 =\",round(T2,2),\"second\"\n",
+    "print\"Change in Reverbration time =\",round(Td,3),\"second\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.6, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "critical field is 33.64 *10**3 ampere/m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=64*10**3;    #initial field(ampere/m)\n",
+    "T=5;    #temperature(K)\n",
+    "Tc=7.26;   #transition temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "H=H0*(1-(T/Tc)**2);     #critical field(ampere/m)\n",
+    "\n",
+    "#Result\n",
+    "print \"critical field is\",round(H/10**3,2),\"*10**3 ampere/m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.7, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency of generated microwaves= 483.0 *10**9 Hz\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19\n",
+    "V=1*10\n",
+    "h=6.625*10**-34\n",
+    "\n",
+    "#Calculations\n",
+    "v=(2*e*V**-3)/h \n",
+    "\n",
+    "#Result\n",
+    "print\"Frequency of generated microwaves=\",round(v/10**9),\"*10**9 Hz\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.8, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of electrons per unit volume = 3.7 *10**28/m**3\n",
+      "Effective mass of electron 'm*' = 17.3 *10*-31 kg\n",
+      "Penetration depth = 3.81011659367 Angstroms\n",
+      "#The answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=7300                  #density in (kg/m**3)\n",
+    "N=6.02*10**26           #Avagadro Number\n",
+    "A=118.7                 #Atomic Weight\n",
+    "E=1.9                 #Effective mass\n",
+    "e=1.6*10**-19\n",
+    "\n",
+    "#Calculations\n",
+    "n=(d*N)/A\n",
+    "m=E*9.1*10**-31\n",
+    "x=4*math.pi*10**-7*n*e**2\n",
+    "lamda_L=math.sqrt(m/x)\n",
+    "      \n",
+    "#Result\n",
+    "print \"Number of electrons per unit volume =\",round(n/10**28,1),\"*10**28/m**3\"\n",
+    "print\"Effective mass of electron 'm*' =\",round(m*10**31,1),\"*10*-31 kg\"\n",
+    "print\"Penetration depth =\",lamda_L*10**8,\"Angstroms\"\n",
+    "print\"#The answer given in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 3.9, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tc = 7.0969 K\n",
+      "lamda0= 39.0 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda_L1=39.6*10**-9\n",
+    "lamda_L2=173*10**-9\n",
+    "T1=7.1\n",
+    "T2=3\n",
+    "\n",
+    "#Calculations\n",
+    "x=(lamda_L1/lamda_L2)**2\n",
+    "Tc4=(T1**4)-((T2**4)*x)/(1-x)\n",
+    "Tc=(Tc4)**(1/4)\n",
+    "print\"Tc =\",round(Tc,4),\"K\"\n",
+    "print\"lamda0=\",round((math.sqrt(1-(T2/Tc)**4)*lamda_L1)*10**9),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.10, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hc = 4.2759 *10**4\n",
+      "Critical current density,Jc = 1.71 *10**8 ampere/metre**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=6.5*10**4           #(ampere/metre)\n",
+    "T=4.2                  #K\n",
+    "Tc=7.18                #K\n",
+    "r=0.5*10**-3\n",
+    "\n",
+    "#Calculations\n",
+    "Hc=H0*(1-(T/Tc)**2)\n",
+    "Ic=(2*math.pi*r)*Hc\n",
+    "A=math.pi*r**2\n",
+    "Jc=Ic/A                #Critical current density\n",
+    "\n",
+    "#Result\n",
+    "print\"Hc =\",round(Hc/10**4,4),\"*10**4\"\n",
+    "print \"Critical current density,Jc =\",round(Jc/10**8,2),\"*10**8 ampere/metre**2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.11, Page number 6.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "New critical temperature for mercury = 4.145 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "Tc1=4.185\n",
+    "M1=199.5\n",
+    "M2=203.4\n",
+    "\n",
+    "#Calculations\n",
+    "Tc2=Tc1*(M1/M2)**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print\"New critical temperature for mercury =\",round(Tc2,3),\"K\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS.ipynb
new file mode 100644
index 00000000..823230a1
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS.ipynb
@@ -0,0 +1,236 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Chapter 4:LASERS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.1, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Divergence = 0.5 *10**-3 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1 = 2;                #in radians\n",
+    "r2 = 3;                #in radians\n",
+    "d1 = 4;                #Converting from mm to radians\n",
+    "d2 = 6;                #Converting from mm to radians\n",
+    "\n",
+    "#calculations\n",
+    "D = (r2-r1)/(d2*10**3-d1*10**3)   #Divergence\n",
+    "\n",
+    "#Result\n",
+    "print \"Divergence =\",round(D*10**3,3),\"*10**-3 radian\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.2, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency (V) = 4.32 *10**14 Hz\n",
+      "Relative Population= 1.081 *10**30\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                    #The speed of light\n",
+    "Lamda=6943                   #Wavelength\n",
+    "T=300                        #Temperature in Kelvin\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "k=1.38*10**-23               #Boltzmann's constant\n",
+    "\n",
+    "#Calculations\n",
+    "\n",
+    "V=(C)/(Lamda*10**-10)       #Frequency\n",
+    "R=math.exp(h*V/(k*T))       #Relative population\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency (V) =\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"Relative Population=\",round(R/10**30,3),\"*10**30\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.3, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Frequency= 4.74 *10**14 Hz\n",
+      "no.of photons emitted= 7.322 *10**15 photons/sec\n",
+      "Power density = 2.3 kWm**-2\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                     #Velocity of light\n",
+    "W=632.8*10**-9                #wavelength\n",
+    "P=2.3\n",
+    "t=1\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "S=1*10**-6\n",
+    "\n",
+    "#Calculations\n",
+    "V=C/W                        #Frequency\n",
+    "n=((P*10**-3)*t)/(h*V)       #no.of photons emitted\n",
+    "PD=P*10**-3/S                #Power density\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency=\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"no.of photons emitted=\",round(n/10**15,3),\"*10**15 photons/sec\"\n",
+    "print \"Power density =\",round(PD/1000,1),\"kWm**-2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.4, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelenght = 8628.0 Angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "C=3*10**8                    #Velocity of light\n",
+    "E_g=1.44                     #bandgap \n",
+    "\n",
+    "#calculations\n",
+    "lamda=(h*C)*10**10/(E_g*1.6*10**-19)       #Wavelenght\n",
+    "\n",
+    "#Result\n",
+    "print \"Wavelenght =\",round(lamda),\"Angstrom\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.5, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Band gap = 0.8 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "W=1.55                       #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "E_g=(1.24)/W                 #Bandgap in eV           \n",
+    "\n",
+    "#Result\n",
+    "print \"Band gap =\",E_g,\"eV\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_1.ipynb
new file mode 100644
index 00000000..823230a1
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_1.ipynb
@@ -0,0 +1,236 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Chapter 4:LASERS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.1, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Divergence = 0.5 *10**-3 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1 = 2;                #in radians\n",
+    "r2 = 3;                #in radians\n",
+    "d1 = 4;                #Converting from mm to radians\n",
+    "d2 = 6;                #Converting from mm to radians\n",
+    "\n",
+    "#calculations\n",
+    "D = (r2-r1)/(d2*10**3-d1*10**3)   #Divergence\n",
+    "\n",
+    "#Result\n",
+    "print \"Divergence =\",round(D*10**3,3),\"*10**-3 radian\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.2, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency (V) = 4.32 *10**14 Hz\n",
+      "Relative Population= 1.081 *10**30\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                    #The speed of light\n",
+    "Lamda=6943                   #Wavelength\n",
+    "T=300                        #Temperature in Kelvin\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "k=1.38*10**-23               #Boltzmann's constant\n",
+    "\n",
+    "#Calculations\n",
+    "\n",
+    "V=(C)/(Lamda*10**-10)       #Frequency\n",
+    "R=math.exp(h*V/(k*T))       #Relative population\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency (V) =\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"Relative Population=\",round(R/10**30,3),\"*10**30\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.3, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Frequency= 4.74 *10**14 Hz\n",
+      "no.of photons emitted= 7.322 *10**15 photons/sec\n",
+      "Power density = 2.3 kWm**-2\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                     #Velocity of light\n",
+    "W=632.8*10**-9                #wavelength\n",
+    "P=2.3\n",
+    "t=1\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "S=1*10**-6\n",
+    "\n",
+    "#Calculations\n",
+    "V=C/W                        #Frequency\n",
+    "n=((P*10**-3)*t)/(h*V)       #no.of photons emitted\n",
+    "PD=P*10**-3/S                #Power density\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency=\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"no.of photons emitted=\",round(n/10**15,3),\"*10**15 photons/sec\"\n",
+    "print \"Power density =\",round(PD/1000,1),\"kWm**-2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.4, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelenght = 8628.0 Angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "C=3*10**8                    #Velocity of light\n",
+    "E_g=1.44                     #bandgap \n",
+    "\n",
+    "#calculations\n",
+    "lamda=(h*C)*10**10/(E_g*1.6*10**-19)       #Wavelenght\n",
+    "\n",
+    "#Result\n",
+    "print \"Wavelenght =\",round(lamda),\"Angstrom\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.5, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Band gap = 0.8 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "W=1.55                       #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "E_g=(1.24)/W                 #Bandgap in eV           \n",
+    "\n",
+    "#Result\n",
+    "print \"Band gap =\",E_g,\"eV\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_2.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_2.ipynb
new file mode 100644
index 00000000..823230a1
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/4.LASERS_2.ipynb
@@ -0,0 +1,236 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Chapter 4:LASERS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.1, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Divergence = 0.5 *10**-3 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1 = 2;                #in radians\n",
+    "r2 = 3;                #in radians\n",
+    "d1 = 4;                #Converting from mm to radians\n",
+    "d2 = 6;                #Converting from mm to radians\n",
+    "\n",
+    "#calculations\n",
+    "D = (r2-r1)/(d2*10**3-d1*10**3)   #Divergence\n",
+    "\n",
+    "#Result\n",
+    "print \"Divergence =\",round(D*10**3,3),\"*10**-3 radian\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.2, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency (V) = 4.32 *10**14 Hz\n",
+      "Relative Population= 1.081 *10**30\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                    #The speed of light\n",
+    "Lamda=6943                   #Wavelength\n",
+    "T=300                        #Temperature in Kelvin\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "k=1.38*10**-23               #Boltzmann's constant\n",
+    "\n",
+    "#Calculations\n",
+    "\n",
+    "V=(C)/(Lamda*10**-10)       #Frequency\n",
+    "R=math.exp(h*V/(k*T))       #Relative population\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency (V) =\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"Relative Population=\",round(R/10**30,3),\"*10**30\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.3, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Frequency= 4.74 *10**14 Hz\n",
+      "no.of photons emitted= 7.322 *10**15 photons/sec\n",
+      "Power density = 2.3 kWm**-2\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                     #Velocity of light\n",
+    "W=632.8*10**-9                #wavelength\n",
+    "P=2.3\n",
+    "t=1\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "S=1*10**-6\n",
+    "\n",
+    "#Calculations\n",
+    "V=C/W                        #Frequency\n",
+    "n=((P*10**-3)*t)/(h*V)       #no.of photons emitted\n",
+    "PD=P*10**-3/S                #Power density\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency=\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"no.of photons emitted=\",round(n/10**15,3),\"*10**15 photons/sec\"\n",
+    "print \"Power density =\",round(PD/1000,1),\"kWm**-2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.4, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelenght = 8628.0 Angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "C=3*10**8                    #Velocity of light\n",
+    "E_g=1.44                     #bandgap \n",
+    "\n",
+    "#calculations\n",
+    "lamda=(h*C)*10**10/(E_g*1.6*10**-19)       #Wavelenght\n",
+    "\n",
+    "#Result\n",
+    "print \"Wavelenght =\",round(lamda),\"Angstrom\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.5, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Band gap = 0.8 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "W=1.55                       #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "E_g=(1.24)/W                 #Bandgap in eV           \n",
+    "\n",
+    "#Result\n",
+    "print \"Band gap =\",E_g,\"eV\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER OPTICS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER OPTICS.ipynb
new file mode 100644
index 00000000..49cd3086
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER OPTICS.ipynb
@@ -0,0 +1,651 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 5:Fiber Optics"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.1, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 125,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The Critical angle = 78.5 degrees\n",
+      "The numerical aperture = 0.3\n",
+      "The acceptance angle = 17.4 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.50          #Core refractive index\n",
+    "n2=1.47          #Cladding refractive index\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)        #Critical angle       \n",
+    "N_a=(n1**2-n2**2)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "\n",
+    "#Results\n",
+    "print \"The Critical angle =\",round(C_a*180/math.pi,1),\"degrees\"\n",
+    "print \"The numerical aperture =\",round(N_a,2)\n",
+    "print \"The acceptance angle =\",round(A_a*180/math.pi,1),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.2, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 126,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 490.0\n",
+      "Fiber can support 490.0 guided modes\n",
+      "In graded index fiber, No.of modes propogated inside the fiber = 245.0 only\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "N_a=0.2             #Numerical aperture\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"N =\",N\n",
+    "print \"Fiber can support\",N,\"guided modes\"\n",
+    "print \"In graded index fiber, No.of modes propogated inside the fiber =\",N/2,\"only\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.3, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.008691\n",
+      "No. of modes that can be propogated = 1.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "n1=1.450\n",
+    "n2=1.447\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Results\n",
+    "print \"Numerical aperture =\",N_a\n",
+    "print \"No. of modes that can be propogated =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.4, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.46\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "delta=0.05          \n",
+    "n1=1.46\n",
+    "\n",
+    "#Calculation\n",
+    "N_a=n1*(2*delta)**(1/2)     #Numerical aperture\n",
+    "\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.5, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "V number = 94.72\n",
+      "maximum no.of modes propogating through fiber = 4486.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=50\n",
+    "n1=1.53\n",
+    "n2=1.50\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "V=((2*math.pi*a)/lamda)*N_a**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print \"V number =\",round(V,2)\n",
+    "print \"maximum no.of modes propogating through fiber =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.6, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 64,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of modes = 24589.0 modes\n",
+      "No.of modes is doubled to account for the two possible polarisations\n",
+      "Total No.of modes = 49178.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=100\n",
+    "N_a=0.3               #Numerical aperture\n",
+    "lamda=850             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=(2*(math.pi)**2*a**2*10**-12*N_a**2)/lamda**2*10**-18\n",
+    "#Result\n",
+    "print \"Number of modes =\",round(V_n/10**-36),\"modes\"\n",
+    "print \"No.of modes is doubled to account for the two possible polarisations\"\n",
+    "print \"Total No.of modes =\",round(V_n/10**-36)*2\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.7, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 88,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Cutoff Wavellength = 1.315 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "a=5;\n",
+    "n1=1.48;\n",
+    "delta=0.01;\n",
+    "V=25;\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(math.pi*(a*10**-6)*n1*math.sqrt(2*delta))/V   # Cutoff Wavelength\n",
+    "\n",
+    "#Result\n",
+    "print \"Cutoff Wavellength =\",round(lamda*10**7,3),\"micro m.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.8, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 87,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Maximum core radius= 9.95 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "V=2.405\n",
+    "lamda=1.3\n",
+    "N_a=0.05\n",
+    "\n",
+    "#Calculations\n",
+    "a_max=(V*lamda)/(2*math.pi*N_a)\n",
+    "\n",
+    "#Result\n",
+    "print \"Maximum core radius=\",round(a_max,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.9, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Acceptance angle, theta_a = 17.46 degrees\n",
+      "For skew rays,theta_as  34.83 degrees\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "N_a=0.3\n",
+    "gamma=45\n",
+    "\n",
+    "#Calculations\n",
+    "theta_a=math.asin(N_a)\n",
+    "theta_as=math.asin((N_a)/math.cos(gamma))\n",
+    "\n",
+    "#Results\n",
+    "print \"Acceptance angle, theta_a =\",round(theta_a*180/math.pi,2),\"degrees\"\n",
+    "print \"For skew rays,theta_as \",round(theta_as*180/math.pi,2),\"degrees\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.10, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 115,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.303\n",
+      "Acceptance angle = 17.63 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.53\n",
+    "delta=0.0196\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=n1*(2*delta)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,3)\n",
+    "print \"Acceptance angle =\",round(A_a*180/math.pi,2),\"degrees\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.11, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "delta = 0.01\n",
+      "Core radius,a = 1.55 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.480\n",
+    "n2=1.465\n",
+    "V=2.405\n",
+    "lamda=850*10**-9\n",
+    "\n",
+    "#Calculations\n",
+    "delta=(n1**2-n2**2)/(2*n1**2)\n",
+    "a=(V*lamda*10**-9)/(2*math.pi*n1*math.sqrt(2*delta))\n",
+    "\n",
+    "#Results\n",
+    "print \"delta =\",round(delta,2)\n",
+    "print \"Core radius,a =\",round(a*10**15,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.12, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 147,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Critical angle= 83.38 degrees\n",
+      "Fiber length covered in one reflection= 430.84 micro m\n",
+      "Total no.of reflections per metre= 2321.0\n",
+      "Since L=1m, Total dist. travelled by light over one metre of fiber = 1.0067 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.5\n",
+    "n2=1.49\n",
+    "a=25\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)           #Critical angle\n",
+    "L=2*a*math.tan(C_a)             \n",
+    "N_r=10**6/L                    \n",
+    "\n",
+    "#Result\n",
+    "print \"Critical angle=\",round(C_a*180/math.pi,2),\"degrees\"\n",
+    "print \"Fiber length covered in one reflection=\",round(L,2),\"micro m\"\n",
+    "print \"Total no.of reflections per metre=\",round(N_r)\n",
+    "print \"Since L=1m, Total dist. travelled by light over one metre of fiber =\",round(1/math.sin(C_a),4),\"m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.13, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 155,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "No.of modes = 154.69 =155(approx)\n",
+      "Taking the two possible polarizations, Total No.of nodes = 309.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "alpha=1.85\n",
+    "lamda=1.3*10**-6\n",
+    "a=25*10**-6\n",
+    "N_a=0.21\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=((2*math.pi**2)*a**2*N_a**2)/lamda**2\n",
+    "N_m=(alpha/(alpha+2))*V_n\n",
+    "\n",
+    "print \"No.of modes =\",round(N_m,2),\"=155(approx)\"\n",
+    "print \"Taking the two possible polarizations, Total No.of nodes =\",round(N_m*2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.14, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a)Signal attention per unit length = 3.9 dB km**-1\n",
+      "b)Overall signal attenuation = 39.0 dB\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "P_i=100\n",
+    "P_o=2\n",
+    "L=10\n",
+    "\n",
+    "#Calculations\n",
+    "S=(10/L)*math.log(P_i/P_o)\n",
+    "O=S*L\n",
+    "\n",
+    "#Result\n",
+    "print \"a)Signal attention per unit length =\",round(S,1),\"dB km**-1\"\n",
+    "print \"b)Overall signal attenuation =\",round(O),\"dB\"\n",
+    "print \"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.15, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total dispersion = 1343.3 ns\n",
+      "Bandwidth length product = 37.22 Hz-km\n",
+      "#Answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "L=10\n",
+    "n1=1.55\n",
+    "delta=0.026\n",
+    "C=3*10**5\n",
+    "\n",
+    "#Calculations\n",
+    "delta_T=(L*n1*delta)/C\n",
+    "B_W=10/(2*delta_T)\n",
+    "\n",
+    "#Result\n",
+    "print \"Total dispersion =\",round(delta_T/10**-9,1),\"ns\"\n",
+    "print \"Bandwidth length product =\",round(B_W/10**5,2),\"Hz-km\"\n",
+    "print \"#Answer given in the text book is wrong\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS.ipynb
new file mode 100644
index 00000000..49cd3086
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS.ipynb
@@ -0,0 +1,651 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 5:Fiber Optics"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.1, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 125,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The Critical angle = 78.5 degrees\n",
+      "The numerical aperture = 0.3\n",
+      "The acceptance angle = 17.4 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.50          #Core refractive index\n",
+    "n2=1.47          #Cladding refractive index\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)        #Critical angle       \n",
+    "N_a=(n1**2-n2**2)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "\n",
+    "#Results\n",
+    "print \"The Critical angle =\",round(C_a*180/math.pi,1),\"degrees\"\n",
+    "print \"The numerical aperture =\",round(N_a,2)\n",
+    "print \"The acceptance angle =\",round(A_a*180/math.pi,1),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.2, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 126,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 490.0\n",
+      "Fiber can support 490.0 guided modes\n",
+      "In graded index fiber, No.of modes propogated inside the fiber = 245.0 only\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "N_a=0.2             #Numerical aperture\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"N =\",N\n",
+    "print \"Fiber can support\",N,\"guided modes\"\n",
+    "print \"In graded index fiber, No.of modes propogated inside the fiber =\",N/2,\"only\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.3, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.008691\n",
+      "No. of modes that can be propogated = 1.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "n1=1.450\n",
+    "n2=1.447\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Results\n",
+    "print \"Numerical aperture =\",N_a\n",
+    "print \"No. of modes that can be propogated =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.4, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.46\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "delta=0.05          \n",
+    "n1=1.46\n",
+    "\n",
+    "#Calculation\n",
+    "N_a=n1*(2*delta)**(1/2)     #Numerical aperture\n",
+    "\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.5, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "V number = 94.72\n",
+      "maximum no.of modes propogating through fiber = 4486.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=50\n",
+    "n1=1.53\n",
+    "n2=1.50\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "V=((2*math.pi*a)/lamda)*N_a**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print \"V number =\",round(V,2)\n",
+    "print \"maximum no.of modes propogating through fiber =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.6, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 64,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of modes = 24589.0 modes\n",
+      "No.of modes is doubled to account for the two possible polarisations\n",
+      "Total No.of modes = 49178.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=100\n",
+    "N_a=0.3               #Numerical aperture\n",
+    "lamda=850             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=(2*(math.pi)**2*a**2*10**-12*N_a**2)/lamda**2*10**-18\n",
+    "#Result\n",
+    "print \"Number of modes =\",round(V_n/10**-36),\"modes\"\n",
+    "print \"No.of modes is doubled to account for the two possible polarisations\"\n",
+    "print \"Total No.of modes =\",round(V_n/10**-36)*2\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.7, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 88,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Cutoff Wavellength = 1.315 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "a=5;\n",
+    "n1=1.48;\n",
+    "delta=0.01;\n",
+    "V=25;\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(math.pi*(a*10**-6)*n1*math.sqrt(2*delta))/V   # Cutoff Wavelength\n",
+    "\n",
+    "#Result\n",
+    "print \"Cutoff Wavellength =\",round(lamda*10**7,3),\"micro m.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.8, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 87,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Maximum core radius= 9.95 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "V=2.405\n",
+    "lamda=1.3\n",
+    "N_a=0.05\n",
+    "\n",
+    "#Calculations\n",
+    "a_max=(V*lamda)/(2*math.pi*N_a)\n",
+    "\n",
+    "#Result\n",
+    "print \"Maximum core radius=\",round(a_max,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.9, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Acceptance angle, theta_a = 17.46 degrees\n",
+      "For skew rays,theta_as  34.83 degrees\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "N_a=0.3\n",
+    "gamma=45\n",
+    "\n",
+    "#Calculations\n",
+    "theta_a=math.asin(N_a)\n",
+    "theta_as=math.asin((N_a)/math.cos(gamma))\n",
+    "\n",
+    "#Results\n",
+    "print \"Acceptance angle, theta_a =\",round(theta_a*180/math.pi,2),\"degrees\"\n",
+    "print \"For skew rays,theta_as \",round(theta_as*180/math.pi,2),\"degrees\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.10, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 115,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.303\n",
+      "Acceptance angle = 17.63 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.53\n",
+    "delta=0.0196\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=n1*(2*delta)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,3)\n",
+    "print \"Acceptance angle =\",round(A_a*180/math.pi,2),\"degrees\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.11, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "delta = 0.01\n",
+      "Core radius,a = 1.55 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.480\n",
+    "n2=1.465\n",
+    "V=2.405\n",
+    "lamda=850*10**-9\n",
+    "\n",
+    "#Calculations\n",
+    "delta=(n1**2-n2**2)/(2*n1**2)\n",
+    "a=(V*lamda*10**-9)/(2*math.pi*n1*math.sqrt(2*delta))\n",
+    "\n",
+    "#Results\n",
+    "print \"delta =\",round(delta,2)\n",
+    "print \"Core radius,a =\",round(a*10**15,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.12, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 147,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Critical angle= 83.38 degrees\n",
+      "Fiber length covered in one reflection= 430.84 micro m\n",
+      "Total no.of reflections per metre= 2321.0\n",
+      "Since L=1m, Total dist. travelled by light over one metre of fiber = 1.0067 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.5\n",
+    "n2=1.49\n",
+    "a=25\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)           #Critical angle\n",
+    "L=2*a*math.tan(C_a)             \n",
+    "N_r=10**6/L                    \n",
+    "\n",
+    "#Result\n",
+    "print \"Critical angle=\",round(C_a*180/math.pi,2),\"degrees\"\n",
+    "print \"Fiber length covered in one reflection=\",round(L,2),\"micro m\"\n",
+    "print \"Total no.of reflections per metre=\",round(N_r)\n",
+    "print \"Since L=1m, Total dist. travelled by light over one metre of fiber =\",round(1/math.sin(C_a),4),\"m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.13, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 155,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "No.of modes = 154.69 =155(approx)\n",
+      "Taking the two possible polarizations, Total No.of nodes = 309.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "alpha=1.85\n",
+    "lamda=1.3*10**-6\n",
+    "a=25*10**-6\n",
+    "N_a=0.21\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=((2*math.pi**2)*a**2*N_a**2)/lamda**2\n",
+    "N_m=(alpha/(alpha+2))*V_n\n",
+    "\n",
+    "print \"No.of modes =\",round(N_m,2),\"=155(approx)\"\n",
+    "print \"Taking the two possible polarizations, Total No.of nodes =\",round(N_m*2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.14, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a)Signal attention per unit length = 3.9 dB km**-1\n",
+      "b)Overall signal attenuation = 39.0 dB\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "P_i=100\n",
+    "P_o=2\n",
+    "L=10\n",
+    "\n",
+    "#Calculations\n",
+    "S=(10/L)*math.log(P_i/P_o)\n",
+    "O=S*L\n",
+    "\n",
+    "#Result\n",
+    "print \"a)Signal attention per unit length =\",round(S,1),\"dB km**-1\"\n",
+    "print \"b)Overall signal attenuation =\",round(O),\"dB\"\n",
+    "print \"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.15, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total dispersion = 1343.3 ns\n",
+      "Bandwidth length product = 37.22 Hz-km\n",
+      "#Answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "L=10\n",
+    "n1=1.55\n",
+    "delta=0.026\n",
+    "C=3*10**5\n",
+    "\n",
+    "#Calculations\n",
+    "delta_T=(L*n1*delta)/C\n",
+    "B_W=10/(2*delta_T)\n",
+    "\n",
+    "#Result\n",
+    "print \"Total dispersion =\",round(delta_T/10**-9,1),\"ns\"\n",
+    "print \"Bandwidth length product =\",round(B_W/10**5,2),\"Hz-km\"\n",
+    "print \"#Answer given in the text book is wrong\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS_1.ipynb
new file mode 100644
index 00000000..49cd3086
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/5.FIBER_OPTICS_1.ipynb
@@ -0,0 +1,651 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 5:Fiber Optics"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.1, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 125,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The Critical angle = 78.5 degrees\n",
+      "The numerical aperture = 0.3\n",
+      "The acceptance angle = 17.4 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.50          #Core refractive index\n",
+    "n2=1.47          #Cladding refractive index\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)        #Critical angle       \n",
+    "N_a=(n1**2-n2**2)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "\n",
+    "#Results\n",
+    "print \"The Critical angle =\",round(C_a*180/math.pi,1),\"degrees\"\n",
+    "print \"The numerical aperture =\",round(N_a,2)\n",
+    "print \"The acceptance angle =\",round(A_a*180/math.pi,1),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.2, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 126,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 490.0\n",
+      "Fiber can support 490.0 guided modes\n",
+      "In graded index fiber, No.of modes propogated inside the fiber = 245.0 only\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "N_a=0.2             #Numerical aperture\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"N =\",N\n",
+    "print \"Fiber can support\",N,\"guided modes\"\n",
+    "print \"In graded index fiber, No.of modes propogated inside the fiber =\",N/2,\"only\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.3, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.008691\n",
+      "No. of modes that can be propogated = 1.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "n1=1.450\n",
+    "n2=1.447\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Results\n",
+    "print \"Numerical aperture =\",N_a\n",
+    "print \"No. of modes that can be propogated =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.4, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.46\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "delta=0.05          \n",
+    "n1=1.46\n",
+    "\n",
+    "#Calculation\n",
+    "N_a=n1*(2*delta)**(1/2)     #Numerical aperture\n",
+    "\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.5, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "V number = 94.72\n",
+      "maximum no.of modes propogating through fiber = 4486.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=50\n",
+    "n1=1.53\n",
+    "n2=1.50\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "V=((2*math.pi*a)/lamda)*N_a**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print \"V number =\",round(V,2)\n",
+    "print \"maximum no.of modes propogating through fiber =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.6, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 64,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of modes = 24589.0 modes\n",
+      "No.of modes is doubled to account for the two possible polarisations\n",
+      "Total No.of modes = 49178.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=100\n",
+    "N_a=0.3               #Numerical aperture\n",
+    "lamda=850             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=(2*(math.pi)**2*a**2*10**-12*N_a**2)/lamda**2*10**-18\n",
+    "#Result\n",
+    "print \"Number of modes =\",round(V_n/10**-36),\"modes\"\n",
+    "print \"No.of modes is doubled to account for the two possible polarisations\"\n",
+    "print \"Total No.of modes =\",round(V_n/10**-36)*2\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.7, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 88,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Cutoff Wavellength = 1.315 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "a=5;\n",
+    "n1=1.48;\n",
+    "delta=0.01;\n",
+    "V=25;\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(math.pi*(a*10**-6)*n1*math.sqrt(2*delta))/V   # Cutoff Wavelength\n",
+    "\n",
+    "#Result\n",
+    "print \"Cutoff Wavellength =\",round(lamda*10**7,3),\"micro m.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.8, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 87,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Maximum core radius= 9.95 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "V=2.405\n",
+    "lamda=1.3\n",
+    "N_a=0.05\n",
+    "\n",
+    "#Calculations\n",
+    "a_max=(V*lamda)/(2*math.pi*N_a)\n",
+    "\n",
+    "#Result\n",
+    "print \"Maximum core radius=\",round(a_max,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.9, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Acceptance angle, theta_a = 17.46 degrees\n",
+      "For skew rays,theta_as  34.83 degrees\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "N_a=0.3\n",
+    "gamma=45\n",
+    "\n",
+    "#Calculations\n",
+    "theta_a=math.asin(N_a)\n",
+    "theta_as=math.asin((N_a)/math.cos(gamma))\n",
+    "\n",
+    "#Results\n",
+    "print \"Acceptance angle, theta_a =\",round(theta_a*180/math.pi,2),\"degrees\"\n",
+    "print \"For skew rays,theta_as \",round(theta_as*180/math.pi,2),\"degrees\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.10, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 115,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.303\n",
+      "Acceptance angle = 17.63 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.53\n",
+    "delta=0.0196\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=n1*(2*delta)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,3)\n",
+    "print \"Acceptance angle =\",round(A_a*180/math.pi,2),\"degrees\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.11, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "delta = 0.01\n",
+      "Core radius,a = 1.55 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.480\n",
+    "n2=1.465\n",
+    "V=2.405\n",
+    "lamda=850*10**-9\n",
+    "\n",
+    "#Calculations\n",
+    "delta=(n1**2-n2**2)/(2*n1**2)\n",
+    "a=(V*lamda*10**-9)/(2*math.pi*n1*math.sqrt(2*delta))\n",
+    "\n",
+    "#Results\n",
+    "print \"delta =\",round(delta,2)\n",
+    "print \"Core radius,a =\",round(a*10**15,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.12, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 147,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Critical angle= 83.38 degrees\n",
+      "Fiber length covered in one reflection= 430.84 micro m\n",
+      "Total no.of reflections per metre= 2321.0\n",
+      "Since L=1m, Total dist. travelled by light over one metre of fiber = 1.0067 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.5\n",
+    "n2=1.49\n",
+    "a=25\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)           #Critical angle\n",
+    "L=2*a*math.tan(C_a)             \n",
+    "N_r=10**6/L                    \n",
+    "\n",
+    "#Result\n",
+    "print \"Critical angle=\",round(C_a*180/math.pi,2),\"degrees\"\n",
+    "print \"Fiber length covered in one reflection=\",round(L,2),\"micro m\"\n",
+    "print \"Total no.of reflections per metre=\",round(N_r)\n",
+    "print \"Since L=1m, Total dist. travelled by light over one metre of fiber =\",round(1/math.sin(C_a),4),\"m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.13, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 155,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "No.of modes = 154.69 =155(approx)\n",
+      "Taking the two possible polarizations, Total No.of nodes = 309.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "alpha=1.85\n",
+    "lamda=1.3*10**-6\n",
+    "a=25*10**-6\n",
+    "N_a=0.21\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=((2*math.pi**2)*a**2*N_a**2)/lamda**2\n",
+    "N_m=(alpha/(alpha+2))*V_n\n",
+    "\n",
+    "print \"No.of modes =\",round(N_m,2),\"=155(approx)\"\n",
+    "print \"Taking the two possible polarizations, Total No.of nodes =\",round(N_m*2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.14, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a)Signal attention per unit length = 3.9 dB km**-1\n",
+      "b)Overall signal attenuation = 39.0 dB\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "P_i=100\n",
+    "P_o=2\n",
+    "L=10\n",
+    "\n",
+    "#Calculations\n",
+    "S=(10/L)*math.log(P_i/P_o)\n",
+    "O=S*L\n",
+    "\n",
+    "#Result\n",
+    "print \"a)Signal attention per unit length =\",round(S,1),\"dB km**-1\"\n",
+    "print \"b)Overall signal attenuation =\",round(O),\"dB\"\n",
+    "print \"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.15, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total dispersion = 1343.3 ns\n",
+      "Bandwidth length product = 37.22 Hz-km\n",
+      "#Answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "L=10\n",
+    "n1=1.55\n",
+    "delta=0.026\n",
+    "C=3*10**5\n",
+    "\n",
+    "#Calculations\n",
+    "delta_T=(L*n1*delta)/C\n",
+    "B_W=10/(2*delta_T)\n",
+    "\n",
+    "#Result\n",
+    "print \"Total dispersion =\",round(delta_T/10**-9,1),\"ns\"\n",
+    "print \"Bandwidth length product =\",round(B_W/10**5,2),\"Hz-km\"\n",
+    "print \"#Answer given in the text book is wrong\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC PROPERTIES AND CRYSTAL STRUCTURES..ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC PROPERTIES AND CRYSTAL STRUCTURES..ipynb
new file mode 100644
index 00000000..392de89d
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC PROPERTIES AND CRYSTAL STRUCTURES..ipynb
@@ -0,0 +1,555 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 6:Magnetic Properties and Crystal Structures"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.1, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "temperature rise is 8.43 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "El=10**-2*50;      #energy loss(J)\n",
+    "H=El*60;           #heat produced(J)\n",
+    "d=7.7*10**3;       #iron rod(kg/m**3)\n",
+    "s=0.462*10**-3;    #specific heat(J/kg K)\n",
+    "\n",
+    "#Calculation\n",
+    "theta=H/(d*s);     #temperature rise(K)\n",
+    "\n",
+    "#Result\n",
+    "print \"temperature rise is\",round(theta,2),\"K\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.2, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "magnetic field at the centre is 14.0 weber/m**2\n",
+      "dipole moment is 9.0 *10**-24 ampere/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19;    #charge(coulomb)\n",
+    "new=6.8*10**15;   #frequency(revolutions per second)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "R=5.1*10**-11;     #radius(m)\n",
+    "\n",
+    "#Calculation\n",
+    "i=round(e*new,4);          #current(ampere)\n",
+    "B=mew0*i/(2*R);            #magnetic field at the centre(weber/m**2)\n",
+    "A=math.pi*R**2;\n",
+    "d=i*A;                    #dipole moment(ampere/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"magnetic field at the centre is\",round(B),\"weber/m**2\"\n",
+    "print \"dipole moment is\",round(d*10**24),\"*10**-24 ampere/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.3, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "intensity of magnetisation is 5.0 ampere/m\n",
+      "flux density in material is 1.257 weber/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "chi=0.5*10**-5;    #magnetic susceptibility\n",
+    "H=10**6;     #field strength(ampere/m)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "\n",
+    "#Calculation\n",
+    "I=chi*H;     #intensity of magnetisation(ampere/m)\n",
+    "B=mew0*(I+H);    #flux density in material(weber/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"intensity of magnetisation is\",I,\"ampere/m\"\n",
+    "print \"flux density in material is\",round(B,3),\"weber/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.4, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of Bohr magnetons is 2.22 bohr magneon/atom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "B=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "a=2.86*10**-10;      #edge(m)\n",
+    "Is=1.76*10**6;       #saturation value of magnetisation(ampere/m)\n",
+    "\n",
+    "#Calculation\n",
+    "N=2/a**3;\n",
+    "mew_bar=Is/N;      #number of Bohr magnetons(ampere m**2)\n",
+    "mew_bar=mew_bar/B;      #number of Bohr magnetons(bohr magneon/atom)\n",
+    "\n",
+    "#Result\n",
+    "print \"number of Bohr magnetons is\",round(mew_bar,2),\"bohr magneon/atom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.5, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "average magnetic moment is 2.79 *10**-3 bohr magneton/spin\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "H=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "beta=10**6;      #field(ampere/m)\n",
+    "k=1.38*10**-23;    #boltzmann constant\n",
+    "T=303;    #temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "mm=mew0*H*beta/(k*T);    #average magnetic moment(bohr magneton/spin)\n",
+    "\n",
+    "#Result\n",
+    "print \"average magnetic moment is\",round(mm*10**3,2),\"*10**-3 bohr magneton/spin\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.6, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hysteresis loss per cycle is 188.0 J/m**3\n",
+      "hysteresis loss per second is 9400.0 watt/m**3\n",
+      "power loss is 1.23 watt/kg\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "A=94;      #area(m**2)\n",
+    "vy=0.1;    #value of length(weber/m**2)\n",
+    "vx=20;     #value of unit length\n",
+    "n=50;      #number of magnetization cycles\n",
+    "d=7650;    #density(kg/m**3)\n",
+    "\n",
+    "#Calculation\n",
+    "h=A*vy*vx;     #hysteresis loss per cycle(J/m**3)\n",
+    "hs=h*n;       #hysteresis loss per second(watt/m**3)\n",
+    "pl=hs/d;      #power loss(watt/kg)\n",
+    "\n",
+    "#Result\n",
+    "print \"hysteresis loss per cycle is\",h,\"J/m**3\"\n",
+    "print \"hysteresis loss per second is\",hs,\"watt/m**3\"\n",
+    "print \"power loss is\",round(pl,2),\"watt/kg\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.7, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 5.43 Angstorm\n",
+      "density = 6.88 kg/m**3\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=2.351                 #bond lenght\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "n=8                     #number of atoms in unit cell\n",
+    "A=28.09                 #Atomin mass of silicon\n",
+    "m=6.02*10**26           #1mole\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*d)/math.sqrt(3)\n",
+    "p=(n*A)/((a*10**-10)*m)    #density\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a,2),\"Angstorm\"\n",
+    "print \"density =\",round(p*10**16,2),\"kg/m**3\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.8, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " radius of largest sphere is 0.154700538379252*r\n",
+      "maximum radius of sphere is 0.414213562373095*r\n"
+     ]
+    }
+   ],
+   "source": [
+    " import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=Symbol('r')\n",
+    "\n",
+    "#Calculation\n",
+    "a1=4*r/math.sqrt(3);\n",
+    "R1=(a1/2)-r;           #radius of largest sphere\n",
+    "a2=4*r/math.sqrt(2);\n",
+    "R2=(a2/2)-r;       #maximum radius of sphere\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of largest sphere is\",R1\n",
+    "print \"maximum radius of sphere is\",R2    "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.9, Page number 6.49"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a1= 2.905 Angstrom\n",
+      "Unit cell volume =a1**3 = 24.521 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.26 *10**-30 m**3\n",
+      "a2= 3.654 Angstorm\n",
+      "Unit cell volume =a2**3 = 48.8 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.2 *10**-30 m**3\n",
+      "Volume Change in % = 0.493\n",
+      "Density Change in % = 0.5\n",
+      "Thus the increase of density or the decrease of volume is about 0.5%\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1=1.258            #Atomic radius of BCC\n",
+    "r2=1.292            #Atomic radius of FCC\n",
+    "\n",
+    "#calculations\n",
+    "a1=(4*r1)/math.sqrt(3)       #in BCC\n",
+    "b1=((a1)**3)*10**-30         #Unit cell volume\n",
+    "v1=(b1)/2                    #Volume occupied by one atom\n",
+    "a2=2*math.sqrt(2)*r2         #in FCC\n",
+    "b2=(a2)**3*10**-30           #Unit cell volume\n",
+    "v2=(b2)/4                    #Volume occupied by one atom  \n",
+    "v_c=((v1)-(v2))*100/(v1)     #Volume Change in % \n",
+    "d_c=((v1)-(v2))*100/(v2)     #Density Change in %\n",
+    "\n",
+    "#Results\n",
+    "print \"a1=\",round(a1,3),\"Angstrom\" \n",
+    "print \"Unit cell volume =a1**3 =\",round((b1)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v1/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"a2=\",round(a2,3),\"Angstorm\"\n",
+    "print \"Unit cell volume =a2**3 =\",round((b2)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v2/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"Volume Change in % =\",round(v_c,3)\n",
+    "print \"Density Change in % =\",round(d_c,2)\n",
+    "print \"Thus the increase of density or the decrease of volume is about 0.5%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.10, Page number 6.50"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 0.563 *10**-9 metre\n",
+      "spacing between the nearest neighbouring ions = 0.2814 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "M=58.5                  #Molecular wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=2180                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*M)/(N*rho))**(1/3)    \n",
+    "s=a/2\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a/10**-9,3),\"*10**-9 metre\"\n",
+    "print \"spacing between the nearest neighbouring ions =\",round(s/10**-9,4),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.11, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant, a= 0.36 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "A=63.55                 #Atomic wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=8930                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*A)/(N*rho))**(1/3)      #Lattice Constant\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant, a=\",round(a*10**9,2),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.12, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Density of iron = 8805.0 kg/m**-3\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "r=0.123                  #Atomic radius\n",
+    "n=4\n",
+    "A=55.8                   #Atomic wt\n",
+    "a=2*math.sqrt(2) \n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "\n",
+    "#Calculations\n",
+    "rho=(n*A)/((a*r*10**-9)**3*N)\n",
+    "\n",
+    "#Result\n",
+    "print \"Density of iron =\",round(rho),\"kg/m**-3\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES..ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES..ipynb
new file mode 100644
index 00000000..392de89d
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES..ipynb
@@ -0,0 +1,555 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 6:Magnetic Properties and Crystal Structures"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.1, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "temperature rise is 8.43 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "El=10**-2*50;      #energy loss(J)\n",
+    "H=El*60;           #heat produced(J)\n",
+    "d=7.7*10**3;       #iron rod(kg/m**3)\n",
+    "s=0.462*10**-3;    #specific heat(J/kg K)\n",
+    "\n",
+    "#Calculation\n",
+    "theta=H/(d*s);     #temperature rise(K)\n",
+    "\n",
+    "#Result\n",
+    "print \"temperature rise is\",round(theta,2),\"K\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.2, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "magnetic field at the centre is 14.0 weber/m**2\n",
+      "dipole moment is 9.0 *10**-24 ampere/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19;    #charge(coulomb)\n",
+    "new=6.8*10**15;   #frequency(revolutions per second)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "R=5.1*10**-11;     #radius(m)\n",
+    "\n",
+    "#Calculation\n",
+    "i=round(e*new,4);          #current(ampere)\n",
+    "B=mew0*i/(2*R);            #magnetic field at the centre(weber/m**2)\n",
+    "A=math.pi*R**2;\n",
+    "d=i*A;                    #dipole moment(ampere/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"magnetic field at the centre is\",round(B),\"weber/m**2\"\n",
+    "print \"dipole moment is\",round(d*10**24),\"*10**-24 ampere/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.3, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "intensity of magnetisation is 5.0 ampere/m\n",
+      "flux density in material is 1.257 weber/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "chi=0.5*10**-5;    #magnetic susceptibility\n",
+    "H=10**6;     #field strength(ampere/m)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "\n",
+    "#Calculation\n",
+    "I=chi*H;     #intensity of magnetisation(ampere/m)\n",
+    "B=mew0*(I+H);    #flux density in material(weber/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"intensity of magnetisation is\",I,\"ampere/m\"\n",
+    "print \"flux density in material is\",round(B,3),\"weber/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.4, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of Bohr magnetons is 2.22 bohr magneon/atom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "B=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "a=2.86*10**-10;      #edge(m)\n",
+    "Is=1.76*10**6;       #saturation value of magnetisation(ampere/m)\n",
+    "\n",
+    "#Calculation\n",
+    "N=2/a**3;\n",
+    "mew_bar=Is/N;      #number of Bohr magnetons(ampere m**2)\n",
+    "mew_bar=mew_bar/B;      #number of Bohr magnetons(bohr magneon/atom)\n",
+    "\n",
+    "#Result\n",
+    "print \"number of Bohr magnetons is\",round(mew_bar,2),\"bohr magneon/atom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.5, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "average magnetic moment is 2.79 *10**-3 bohr magneton/spin\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "H=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "beta=10**6;      #field(ampere/m)\n",
+    "k=1.38*10**-23;    #boltzmann constant\n",
+    "T=303;    #temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "mm=mew0*H*beta/(k*T);    #average magnetic moment(bohr magneton/spin)\n",
+    "\n",
+    "#Result\n",
+    "print \"average magnetic moment is\",round(mm*10**3,2),\"*10**-3 bohr magneton/spin\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.6, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hysteresis loss per cycle is 188.0 J/m**3\n",
+      "hysteresis loss per second is 9400.0 watt/m**3\n",
+      "power loss is 1.23 watt/kg\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "A=94;      #area(m**2)\n",
+    "vy=0.1;    #value of length(weber/m**2)\n",
+    "vx=20;     #value of unit length\n",
+    "n=50;      #number of magnetization cycles\n",
+    "d=7650;    #density(kg/m**3)\n",
+    "\n",
+    "#Calculation\n",
+    "h=A*vy*vx;     #hysteresis loss per cycle(J/m**3)\n",
+    "hs=h*n;       #hysteresis loss per second(watt/m**3)\n",
+    "pl=hs/d;      #power loss(watt/kg)\n",
+    "\n",
+    "#Result\n",
+    "print \"hysteresis loss per cycle is\",h,\"J/m**3\"\n",
+    "print \"hysteresis loss per second is\",hs,\"watt/m**3\"\n",
+    "print \"power loss is\",round(pl,2),\"watt/kg\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.7, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 5.43 Angstorm\n",
+      "density = 6.88 kg/m**3\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=2.351                 #bond lenght\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "n=8                     #number of atoms in unit cell\n",
+    "A=28.09                 #Atomin mass of silicon\n",
+    "m=6.02*10**26           #1mole\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*d)/math.sqrt(3)\n",
+    "p=(n*A)/((a*10**-10)*m)    #density\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a,2),\"Angstorm\"\n",
+    "print \"density =\",round(p*10**16,2),\"kg/m**3\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.8, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " radius of largest sphere is 0.154700538379252*r\n",
+      "maximum radius of sphere is 0.414213562373095*r\n"
+     ]
+    }
+   ],
+   "source": [
+    " import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=Symbol('r')\n",
+    "\n",
+    "#Calculation\n",
+    "a1=4*r/math.sqrt(3);\n",
+    "R1=(a1/2)-r;           #radius of largest sphere\n",
+    "a2=4*r/math.sqrt(2);\n",
+    "R2=(a2/2)-r;       #maximum radius of sphere\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of largest sphere is\",R1\n",
+    "print \"maximum radius of sphere is\",R2    "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.9, Page number 6.49"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a1= 2.905 Angstrom\n",
+      "Unit cell volume =a1**3 = 24.521 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.26 *10**-30 m**3\n",
+      "a2= 3.654 Angstorm\n",
+      "Unit cell volume =a2**3 = 48.8 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.2 *10**-30 m**3\n",
+      "Volume Change in % = 0.493\n",
+      "Density Change in % = 0.5\n",
+      "Thus the increase of density or the decrease of volume is about 0.5%\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1=1.258            #Atomic radius of BCC\n",
+    "r2=1.292            #Atomic radius of FCC\n",
+    "\n",
+    "#calculations\n",
+    "a1=(4*r1)/math.sqrt(3)       #in BCC\n",
+    "b1=((a1)**3)*10**-30         #Unit cell volume\n",
+    "v1=(b1)/2                    #Volume occupied by one atom\n",
+    "a2=2*math.sqrt(2)*r2         #in FCC\n",
+    "b2=(a2)**3*10**-30           #Unit cell volume\n",
+    "v2=(b2)/4                    #Volume occupied by one atom  \n",
+    "v_c=((v1)-(v2))*100/(v1)     #Volume Change in % \n",
+    "d_c=((v1)-(v2))*100/(v2)     #Density Change in %\n",
+    "\n",
+    "#Results\n",
+    "print \"a1=\",round(a1,3),\"Angstrom\" \n",
+    "print \"Unit cell volume =a1**3 =\",round((b1)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v1/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"a2=\",round(a2,3),\"Angstorm\"\n",
+    "print \"Unit cell volume =a2**3 =\",round((b2)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v2/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"Volume Change in % =\",round(v_c,3)\n",
+    "print \"Density Change in % =\",round(d_c,2)\n",
+    "print \"Thus the increase of density or the decrease of volume is about 0.5%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.10, Page number 6.50"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 0.563 *10**-9 metre\n",
+      "spacing between the nearest neighbouring ions = 0.2814 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "M=58.5                  #Molecular wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=2180                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*M)/(N*rho))**(1/3)    \n",
+    "s=a/2\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a/10**-9,3),\"*10**-9 metre\"\n",
+    "print \"spacing between the nearest neighbouring ions =\",round(s/10**-9,4),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.11, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant, a= 0.36 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "A=63.55                 #Atomic wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=8930                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*A)/(N*rho))**(1/3)      #Lattice Constant\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant, a=\",round(a*10**9,2),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.12, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Density of iron = 8805.0 kg/m**-3\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "r=0.123                  #Atomic radius\n",
+    "n=4\n",
+    "A=55.8                   #Atomic wt\n",
+    "a=2*math.sqrt(2) \n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "\n",
+    "#Calculations\n",
+    "rho=(n*A)/((a*r*10**-9)**3*N)\n",
+    "\n",
+    "#Result\n",
+    "print \"Density of iron =\",round(rho),\"kg/m**-3\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES._1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES._1.ipynb
new file mode 100644
index 00000000..392de89d
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/6.MAGNETIC_PROPERTIES_AND_CRYSTAL_STRUCTURES._1.ipynb
@@ -0,0 +1,555 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 6:Magnetic Properties and Crystal Structures"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.1, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "temperature rise is 8.43 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "El=10**-2*50;      #energy loss(J)\n",
+    "H=El*60;           #heat produced(J)\n",
+    "d=7.7*10**3;       #iron rod(kg/m**3)\n",
+    "s=0.462*10**-3;    #specific heat(J/kg K)\n",
+    "\n",
+    "#Calculation\n",
+    "theta=H/(d*s);     #temperature rise(K)\n",
+    "\n",
+    "#Result\n",
+    "print \"temperature rise is\",round(theta,2),\"K\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.2, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "magnetic field at the centre is 14.0 weber/m**2\n",
+      "dipole moment is 9.0 *10**-24 ampere/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19;    #charge(coulomb)\n",
+    "new=6.8*10**15;   #frequency(revolutions per second)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "R=5.1*10**-11;     #radius(m)\n",
+    "\n",
+    "#Calculation\n",
+    "i=round(e*new,4);          #current(ampere)\n",
+    "B=mew0*i/(2*R);            #magnetic field at the centre(weber/m**2)\n",
+    "A=math.pi*R**2;\n",
+    "d=i*A;                    #dipole moment(ampere/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"magnetic field at the centre is\",round(B),\"weber/m**2\"\n",
+    "print \"dipole moment is\",round(d*10**24),\"*10**-24 ampere/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.3, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "intensity of magnetisation is 5.0 ampere/m\n",
+      "flux density in material is 1.257 weber/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "chi=0.5*10**-5;    #magnetic susceptibility\n",
+    "H=10**6;     #field strength(ampere/m)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "\n",
+    "#Calculation\n",
+    "I=chi*H;     #intensity of magnetisation(ampere/m)\n",
+    "B=mew0*(I+H);    #flux density in material(weber/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"intensity of magnetisation is\",I,\"ampere/m\"\n",
+    "print \"flux density in material is\",round(B,3),\"weber/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.4, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of Bohr magnetons is 2.22 bohr magneon/atom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "B=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "a=2.86*10**-10;      #edge(m)\n",
+    "Is=1.76*10**6;       #saturation value of magnetisation(ampere/m)\n",
+    "\n",
+    "#Calculation\n",
+    "N=2/a**3;\n",
+    "mew_bar=Is/N;      #number of Bohr magnetons(ampere m**2)\n",
+    "mew_bar=mew_bar/B;      #number of Bohr magnetons(bohr magneon/atom)\n",
+    "\n",
+    "#Result\n",
+    "print \"number of Bohr magnetons is\",round(mew_bar,2),\"bohr magneon/atom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.5, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "average magnetic moment is 2.79 *10**-3 bohr magneton/spin\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "H=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "beta=10**6;      #field(ampere/m)\n",
+    "k=1.38*10**-23;    #boltzmann constant\n",
+    "T=303;    #temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "mm=mew0*H*beta/(k*T);    #average magnetic moment(bohr magneton/spin)\n",
+    "\n",
+    "#Result\n",
+    "print \"average magnetic moment is\",round(mm*10**3,2),\"*10**-3 bohr magneton/spin\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.6, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hysteresis loss per cycle is 188.0 J/m**3\n",
+      "hysteresis loss per second is 9400.0 watt/m**3\n",
+      "power loss is 1.23 watt/kg\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "A=94;      #area(m**2)\n",
+    "vy=0.1;    #value of length(weber/m**2)\n",
+    "vx=20;     #value of unit length\n",
+    "n=50;      #number of magnetization cycles\n",
+    "d=7650;    #density(kg/m**3)\n",
+    "\n",
+    "#Calculation\n",
+    "h=A*vy*vx;     #hysteresis loss per cycle(J/m**3)\n",
+    "hs=h*n;       #hysteresis loss per second(watt/m**3)\n",
+    "pl=hs/d;      #power loss(watt/kg)\n",
+    "\n",
+    "#Result\n",
+    "print \"hysteresis loss per cycle is\",h,\"J/m**3\"\n",
+    "print \"hysteresis loss per second is\",hs,\"watt/m**3\"\n",
+    "print \"power loss is\",round(pl,2),\"watt/kg\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.7, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 5.43 Angstorm\n",
+      "density = 6.88 kg/m**3\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=2.351                 #bond lenght\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "n=8                     #number of atoms in unit cell\n",
+    "A=28.09                 #Atomin mass of silicon\n",
+    "m=6.02*10**26           #1mole\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*d)/math.sqrt(3)\n",
+    "p=(n*A)/((a*10**-10)*m)    #density\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a,2),\"Angstorm\"\n",
+    "print \"density =\",round(p*10**16,2),\"kg/m**3\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.8, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " radius of largest sphere is 0.154700538379252*r\n",
+      "maximum radius of sphere is 0.414213562373095*r\n"
+     ]
+    }
+   ],
+   "source": [
+    " import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=Symbol('r')\n",
+    "\n",
+    "#Calculation\n",
+    "a1=4*r/math.sqrt(3);\n",
+    "R1=(a1/2)-r;           #radius of largest sphere\n",
+    "a2=4*r/math.sqrt(2);\n",
+    "R2=(a2/2)-r;       #maximum radius of sphere\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of largest sphere is\",R1\n",
+    "print \"maximum radius of sphere is\",R2    "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.9, Page number 6.49"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a1= 2.905 Angstrom\n",
+      "Unit cell volume =a1**3 = 24.521 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.26 *10**-30 m**3\n",
+      "a2= 3.654 Angstorm\n",
+      "Unit cell volume =a2**3 = 48.8 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.2 *10**-30 m**3\n",
+      "Volume Change in % = 0.493\n",
+      "Density Change in % = 0.5\n",
+      "Thus the increase of density or the decrease of volume is about 0.5%\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1=1.258            #Atomic radius of BCC\n",
+    "r2=1.292            #Atomic radius of FCC\n",
+    "\n",
+    "#calculations\n",
+    "a1=(4*r1)/math.sqrt(3)       #in BCC\n",
+    "b1=((a1)**3)*10**-30         #Unit cell volume\n",
+    "v1=(b1)/2                    #Volume occupied by one atom\n",
+    "a2=2*math.sqrt(2)*r2         #in FCC\n",
+    "b2=(a2)**3*10**-30           #Unit cell volume\n",
+    "v2=(b2)/4                    #Volume occupied by one atom  \n",
+    "v_c=((v1)-(v2))*100/(v1)     #Volume Change in % \n",
+    "d_c=((v1)-(v2))*100/(v2)     #Density Change in %\n",
+    "\n",
+    "#Results\n",
+    "print \"a1=\",round(a1,3),\"Angstrom\" \n",
+    "print \"Unit cell volume =a1**3 =\",round((b1)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v1/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"a2=\",round(a2,3),\"Angstorm\"\n",
+    "print \"Unit cell volume =a2**3 =\",round((b2)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v2/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"Volume Change in % =\",round(v_c,3)\n",
+    "print \"Density Change in % =\",round(d_c,2)\n",
+    "print \"Thus the increase of density or the decrease of volume is about 0.5%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.10, Page number 6.50"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 0.563 *10**-9 metre\n",
+      "spacing between the nearest neighbouring ions = 0.2814 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "M=58.5                  #Molecular wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=2180                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*M)/(N*rho))**(1/3)    \n",
+    "s=a/2\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a/10**-9,3),\"*10**-9 metre\"\n",
+    "print \"spacing between the nearest neighbouring ions =\",round(s/10**-9,4),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.11, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant, a= 0.36 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "A=63.55                 #Atomic wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=8930                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*A)/(N*rho))**(1/3)      #Lattice Constant\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant, a=\",round(a*10**9,2),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.12, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Density of iron = 8805.0 kg/m**-3\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "r=0.123                  #Atomic radius\n",
+    "n=4\n",
+    "A=55.8                   #Atomic wt\n",
+    "a=2*math.sqrt(2) \n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "\n",
+    "#Calculations\n",
+    "rho=(n*A)/((a*r*10**-9)**3*N)\n",
+    "\n",
+    "#Result\n",
+    "print \"Density of iron =\",round(rho),\"kg/m**-3\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL STRUCTURES AND X-RAY DIFFRACTION.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL STRUCTURES AND X-RAY DIFFRACTION.ipynb
new file mode 100644
index 00000000..884fa904
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL STRUCTURES AND X-RAY DIFFRACTION.ipynb
@@ -0,0 +1,615 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#7: Crystal Planes and X-ray Diffraction"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.1, Page number 7.12"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Number of atoms per unit area of (100)plane= 1/(4*R**2)\n",
+      "ii)Number of atoms per unit area of (110)plane= 2.82842712474619*R**2\n",
+      "iii)Number of atoms per unit area of (111)plane= 2.3094010767585*R**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "#Variable declaration\n",
+    "R=Symbol('R')\n",
+    "a=2*R\n",
+    "\n",
+    "#Results\n",
+    "print\"i)Number of atoms per unit area of (100)plane=\",1/a**2\n",
+    "print\"ii)Number of atoms per unit area of (110)plane=\",1/math.sqrt(2)*a**2\n",
+    "print\"iii)Number of atoms per unit area of (111)plane=\",1/math.sqrt(3)*a**2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.2, Page number 7.13"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Surface area of the face ABCD = 13.0 *10**-14 mm**2\n",
+      "ii)Surface area of plane (110) = 1.09 *10**13 atoms/mm**2\n",
+      "iii)Surface area of pane(111)= 1.772 *10**13 atoms/mm**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.61*10**-7\n",
+    "BC=math.sqrt(2)/2\n",
+    "AD=(math.sqrt(6))/2\n",
+    "#Result\n",
+    "print\"i)Surface area of the face ABCD =\",round(a**2*10**14),\"*10**-14 mm**2\"\n",
+    "print\"ii)Surface area of plane (110) =\",round((2/(a*math.sqrt(2)*a)/10**13),2),\"*10**13 atoms/mm**2\"\n",
+    "print\"iii)Surface area of pane(111)=\",round(2/(BC*AD*a**2)*10**-13,3),\"*10**13 atoms/mm**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.3, Page number 7.14"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d1 = 1.0\n",
+      "d2 = 0.707\n",
+      "d3 = 0.577\n",
+      "d1:d2:d3 = 1.0 : 0.707 : 0.577\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h1=1\n",
+    "k1=0\n",
+    "l1=0\n",
+    "h2=1\n",
+    "k2=1\n",
+    "l2=0\n",
+    "h3=1\n",
+    "k3=1\n",
+    "l3=1\n",
+    "a=1\n",
+    "\n",
+    "#Calculations\n",
+    "d1=a/(math.sqrt(h1**2+k1**2+l1**2))\n",
+    "d2=a/(math.sqrt(h2**2+k2**2+l2**2))\n",
+    "d3=a/(math.sqrt(h3**2+k3**2+l3**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d1 =\",d1 \n",
+    "print\"d2 =\",round(d2,3)\n",
+    "print\"d3 =\",round(d3,3)\n",
+    "print\"d1:d2:d3 =\",d1,\":\",round(d2,3),\":\",round(d3,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.4, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d(220) = 159.1 pm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "a=450\n",
+    "\n",
+    "#Calculations\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d(220) =\",round(d,1),\"pm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.5, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.615 Angstroms\n",
+      "d = 2.087 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.615\n",
+    "r=1.278\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*r)/math.sqrt(2)\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,3),\"Angstroms\"\n",
+    "print\"d =\",round(d,3),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.7, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 1.45 *10**-10 m\n",
+      "a = 4.1 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=1\n",
+    "lamda=1.54\n",
+    "theta=32*math.pi/180\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda*10**-10)/(2*math.sin(theta))   #derived from 2dsin(theta)=n*l\n",
+    "a=d*(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Results\n",
+    "print\"d =\",round(d*10**10,2),\"*10**-10 m\"\n",
+    "print\"a =\",round(a*10**10,1),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.8, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 50,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i.  d/n = 2.582 Angstroms\n",
+      "ii. d/n = 1.824 Angstroms\n",
+      "iii.d/n = 1.289 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta1=6.45*math.pi/180\n",
+    "theta2=9.15*math.pi/180\n",
+    "theta3=13*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "dbyn1=lamda/(2*(math.sin(theta1)))\n",
+    "dbyn2=lamda/(2*math.sin(theta2))\n",
+    "dbyn3=lamda/(2*math.sin(theta3))\n",
+    "           \n",
+    "#Results\n",
+    "print\"i.  d/n =\",round(dbyn1,3),\"Angstroms\"\n",
+    "print\"ii. d/n =\",round(dbyn2,3),\"Angstroms\"\n",
+    "print\"iii.d/n =\",round(dbyn3,3),\"Angstroms\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.9, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "n = 1.53\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1.18\n",
+    "theta=90*math.pi/180\n",
+    "lamda=1.540\n",
+    "\n",
+    "#Calculations\n",
+    "n=(2*d*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"n =\",round(n,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.10, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.51 Angstorms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta=9.5*math.pi/180\n",
+    "n=1\n",
+    "d=0.5           #d200=a/math.sqrt(2**2+0**2+0**2)=0.5a\n",
+    "#Calculations\n",
+    "a=n*lamda/(2*d*math.sin(theta))     #2*d*sin(theta)=n*lamda \n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstorms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.11, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sin(theta3) = 26 35.9387574495\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.842\n",
+    "n1=1\n",
+    "q=(8+(35/60))*(math.pi/180)\n",
+    "n2=3\n",
+    "d=1\n",
+    "#Calculations\n",
+    "#n*lamda=2*d*sin(theta)\n",
+    "#n1*0.842=2*d*sin(q)\n",
+    "#n3*0.842=2*d*sin(theta3)\n",
+    "#Dividing both the eauations, we get\n",
+    "#(n2*lamda)/(n1*lamda)=2*d*math.sin(theta3)/2*d*math.sin(q)\n",
+    "theta3=math.asin((((n2*lamda)/(n1*lamda))*(2*d*math.sin(q)))/(2*d))\n",
+    "d=theta3*180/math.pi;\n",
+    "a_d=int(d);\n",
+    "a_m=(d-int(d))*60\n",
+    "\n",
+    "#Result\n",
+    "print\"sin(theta3) =\",a_d,a_m\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.12, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.22 Angstorms\n",
+      "sqrt(h**2+k**2+l**2) = 1.424\n",
+      "Therefore, h**2+k**2+l**2 =sqrt(2)\n",
+      "h =1, k=1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.16\n",
+    "lamda=1.54\n",
+    "n=1\n",
+    "theta=20.3*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda)/(2*math.sin(theta))\n",
+    "x=a/d                             #let math.sqrt(h**2+k**2+l**2)=x\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sqrt(h**2+k**2+l**2) =\",round(x,3)\n",
+    "print\"Therefore, h**2+k**2+l**2 =sqrt(2)\"\n",
+    "print\"h =1, k=1\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.13, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 4.09 Angstroms\n",
+      "d = 2.36 Angstroms\n",
+      "lamda = 1.552 Angstroms\n",
+      "E = 8.0 *10**3 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "## importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=4\n",
+    "A=107.87\n",
+    "rho=10500\n",
+    "N=6.02*10**26\n",
+    "h=1;\n",
+    "k=1;\n",
+    "l=1;\n",
+    "H=6.625*10**-34\n",
+    "e=1.6*10**-19\n",
+    "theta=(19+(12/60))*math.pi/180\n",
+    "C=3*10**8\n",
+    "#Calculations\n",
+    "a=((n*A)/(rho*N))**(1/3)*10**10\n",
+    "d=a/math.sqrt(h**2+k**2+l**2)\n",
+    "lamda=2*d*math.sin(theta)\n",
+    "E=(H*C)/(lamda*10**-10*e)\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstroms\"\n",
+    "print\"d =\",round(d,2),\"Angstroms\"\n",
+    "print\"lamda =\",round(lamda,3),\"Angstroms\"\n",
+    "print\"E =\",round(E/10**3),\"*10**3 eV\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.14, Page number 7.19"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 72,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.64 Angstorms\n",
+      "sin(theta)= 0.288\n",
+      "X = 7.554 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=4.57\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "lamda=1.52\n",
+    "twotheta=33.5*math.pi/180\n",
+    "r=5                  #radius\n",
+    "#Calculations\n",
+    "d=a/(h**2+k**2+l**2)**(1/2)\n",
+    "sintheta=lamda/(2*d)\n",
+    "X=r/math.tan(twotheta)\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sin(theta)=\",round(sintheta,3)\n",
+    "print\"X =\",round(X,3),\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION.ipynb
new file mode 100644
index 00000000..884fa904
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION.ipynb
@@ -0,0 +1,615 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#7: Crystal Planes and X-ray Diffraction"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.1, Page number 7.12"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Number of atoms per unit area of (100)plane= 1/(4*R**2)\n",
+      "ii)Number of atoms per unit area of (110)plane= 2.82842712474619*R**2\n",
+      "iii)Number of atoms per unit area of (111)plane= 2.3094010767585*R**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "#Variable declaration\n",
+    "R=Symbol('R')\n",
+    "a=2*R\n",
+    "\n",
+    "#Results\n",
+    "print\"i)Number of atoms per unit area of (100)plane=\",1/a**2\n",
+    "print\"ii)Number of atoms per unit area of (110)plane=\",1/math.sqrt(2)*a**2\n",
+    "print\"iii)Number of atoms per unit area of (111)plane=\",1/math.sqrt(3)*a**2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.2, Page number 7.13"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Surface area of the face ABCD = 13.0 *10**-14 mm**2\n",
+      "ii)Surface area of plane (110) = 1.09 *10**13 atoms/mm**2\n",
+      "iii)Surface area of pane(111)= 1.772 *10**13 atoms/mm**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.61*10**-7\n",
+    "BC=math.sqrt(2)/2\n",
+    "AD=(math.sqrt(6))/2\n",
+    "#Result\n",
+    "print\"i)Surface area of the face ABCD =\",round(a**2*10**14),\"*10**-14 mm**2\"\n",
+    "print\"ii)Surface area of plane (110) =\",round((2/(a*math.sqrt(2)*a)/10**13),2),\"*10**13 atoms/mm**2\"\n",
+    "print\"iii)Surface area of pane(111)=\",round(2/(BC*AD*a**2)*10**-13,3),\"*10**13 atoms/mm**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.3, Page number 7.14"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d1 = 1.0\n",
+      "d2 = 0.707\n",
+      "d3 = 0.577\n",
+      "d1:d2:d3 = 1.0 : 0.707 : 0.577\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h1=1\n",
+    "k1=0\n",
+    "l1=0\n",
+    "h2=1\n",
+    "k2=1\n",
+    "l2=0\n",
+    "h3=1\n",
+    "k3=1\n",
+    "l3=1\n",
+    "a=1\n",
+    "\n",
+    "#Calculations\n",
+    "d1=a/(math.sqrt(h1**2+k1**2+l1**2))\n",
+    "d2=a/(math.sqrt(h2**2+k2**2+l2**2))\n",
+    "d3=a/(math.sqrt(h3**2+k3**2+l3**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d1 =\",d1 \n",
+    "print\"d2 =\",round(d2,3)\n",
+    "print\"d3 =\",round(d3,3)\n",
+    "print\"d1:d2:d3 =\",d1,\":\",round(d2,3),\":\",round(d3,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.4, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d(220) = 159.1 pm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "a=450\n",
+    "\n",
+    "#Calculations\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d(220) =\",round(d,1),\"pm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.5, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.615 Angstroms\n",
+      "d = 2.087 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.615\n",
+    "r=1.278\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*r)/math.sqrt(2)\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,3),\"Angstroms\"\n",
+    "print\"d =\",round(d,3),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.7, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 1.45 *10**-10 m\n",
+      "a = 4.1 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=1\n",
+    "lamda=1.54\n",
+    "theta=32*math.pi/180\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda*10**-10)/(2*math.sin(theta))   #derived from 2dsin(theta)=n*l\n",
+    "a=d*(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Results\n",
+    "print\"d =\",round(d*10**10,2),\"*10**-10 m\"\n",
+    "print\"a =\",round(a*10**10,1),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.8, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 50,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i.  d/n = 2.582 Angstroms\n",
+      "ii. d/n = 1.824 Angstroms\n",
+      "iii.d/n = 1.289 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta1=6.45*math.pi/180\n",
+    "theta2=9.15*math.pi/180\n",
+    "theta3=13*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "dbyn1=lamda/(2*(math.sin(theta1)))\n",
+    "dbyn2=lamda/(2*math.sin(theta2))\n",
+    "dbyn3=lamda/(2*math.sin(theta3))\n",
+    "           \n",
+    "#Results\n",
+    "print\"i.  d/n =\",round(dbyn1,3),\"Angstroms\"\n",
+    "print\"ii. d/n =\",round(dbyn2,3),\"Angstroms\"\n",
+    "print\"iii.d/n =\",round(dbyn3,3),\"Angstroms\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.9, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "n = 1.53\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1.18\n",
+    "theta=90*math.pi/180\n",
+    "lamda=1.540\n",
+    "\n",
+    "#Calculations\n",
+    "n=(2*d*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"n =\",round(n,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.10, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.51 Angstorms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta=9.5*math.pi/180\n",
+    "n=1\n",
+    "d=0.5           #d200=a/math.sqrt(2**2+0**2+0**2)=0.5a\n",
+    "#Calculations\n",
+    "a=n*lamda/(2*d*math.sin(theta))     #2*d*sin(theta)=n*lamda \n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstorms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.11, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sin(theta3) = 26 35.9387574495\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.842\n",
+    "n1=1\n",
+    "q=(8+(35/60))*(math.pi/180)\n",
+    "n2=3\n",
+    "d=1\n",
+    "#Calculations\n",
+    "#n*lamda=2*d*sin(theta)\n",
+    "#n1*0.842=2*d*sin(q)\n",
+    "#n3*0.842=2*d*sin(theta3)\n",
+    "#Dividing both the eauations, we get\n",
+    "#(n2*lamda)/(n1*lamda)=2*d*math.sin(theta3)/2*d*math.sin(q)\n",
+    "theta3=math.asin((((n2*lamda)/(n1*lamda))*(2*d*math.sin(q)))/(2*d))\n",
+    "d=theta3*180/math.pi;\n",
+    "a_d=int(d);\n",
+    "a_m=(d-int(d))*60\n",
+    "\n",
+    "#Result\n",
+    "print\"sin(theta3) =\",a_d,a_m\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.12, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.22 Angstorms\n",
+      "sqrt(h**2+k**2+l**2) = 1.424\n",
+      "Therefore, h**2+k**2+l**2 =sqrt(2)\n",
+      "h =1, k=1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.16\n",
+    "lamda=1.54\n",
+    "n=1\n",
+    "theta=20.3*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda)/(2*math.sin(theta))\n",
+    "x=a/d                             #let math.sqrt(h**2+k**2+l**2)=x\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sqrt(h**2+k**2+l**2) =\",round(x,3)\n",
+    "print\"Therefore, h**2+k**2+l**2 =sqrt(2)\"\n",
+    "print\"h =1, k=1\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.13, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 4.09 Angstroms\n",
+      "d = 2.36 Angstroms\n",
+      "lamda = 1.552 Angstroms\n",
+      "E = 8.0 *10**3 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "## importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=4\n",
+    "A=107.87\n",
+    "rho=10500\n",
+    "N=6.02*10**26\n",
+    "h=1;\n",
+    "k=1;\n",
+    "l=1;\n",
+    "H=6.625*10**-34\n",
+    "e=1.6*10**-19\n",
+    "theta=(19+(12/60))*math.pi/180\n",
+    "C=3*10**8\n",
+    "#Calculations\n",
+    "a=((n*A)/(rho*N))**(1/3)*10**10\n",
+    "d=a/math.sqrt(h**2+k**2+l**2)\n",
+    "lamda=2*d*math.sin(theta)\n",
+    "E=(H*C)/(lamda*10**-10*e)\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstroms\"\n",
+    "print\"d =\",round(d,2),\"Angstroms\"\n",
+    "print\"lamda =\",round(lamda,3),\"Angstroms\"\n",
+    "print\"E =\",round(E/10**3),\"*10**3 eV\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.14, Page number 7.19"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 72,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.64 Angstorms\n",
+      "sin(theta)= 0.288\n",
+      "X = 7.554 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=4.57\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "lamda=1.52\n",
+    "twotheta=33.5*math.pi/180\n",
+    "r=5                  #radius\n",
+    "#Calculations\n",
+    "d=a/(h**2+k**2+l**2)**(1/2)\n",
+    "sintheta=lamda/(2*d)\n",
+    "X=r/math.tan(twotheta)\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sin(theta)=\",round(sintheta,3)\n",
+    "print\"X =\",round(X,3),\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION_1.ipynb
new file mode 100644
index 00000000..884fa904
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/7.CRYSTAL_STRUCTURES_AND_X-RAY_DIFFRACTION_1.ipynb
@@ -0,0 +1,615 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#7: Crystal Planes and X-ray Diffraction"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.1, Page number 7.12"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Number of atoms per unit area of (100)plane= 1/(4*R**2)\n",
+      "ii)Number of atoms per unit area of (110)plane= 2.82842712474619*R**2\n",
+      "iii)Number of atoms per unit area of (111)plane= 2.3094010767585*R**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "#Variable declaration\n",
+    "R=Symbol('R')\n",
+    "a=2*R\n",
+    "\n",
+    "#Results\n",
+    "print\"i)Number of atoms per unit area of (100)plane=\",1/a**2\n",
+    "print\"ii)Number of atoms per unit area of (110)plane=\",1/math.sqrt(2)*a**2\n",
+    "print\"iii)Number of atoms per unit area of (111)plane=\",1/math.sqrt(3)*a**2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.2, Page number 7.13"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Surface area of the face ABCD = 13.0 *10**-14 mm**2\n",
+      "ii)Surface area of plane (110) = 1.09 *10**13 atoms/mm**2\n",
+      "iii)Surface area of pane(111)= 1.772 *10**13 atoms/mm**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.61*10**-7\n",
+    "BC=math.sqrt(2)/2\n",
+    "AD=(math.sqrt(6))/2\n",
+    "#Result\n",
+    "print\"i)Surface area of the face ABCD =\",round(a**2*10**14),\"*10**-14 mm**2\"\n",
+    "print\"ii)Surface area of plane (110) =\",round((2/(a*math.sqrt(2)*a)/10**13),2),\"*10**13 atoms/mm**2\"\n",
+    "print\"iii)Surface area of pane(111)=\",round(2/(BC*AD*a**2)*10**-13,3),\"*10**13 atoms/mm**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.3, Page number 7.14"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d1 = 1.0\n",
+      "d2 = 0.707\n",
+      "d3 = 0.577\n",
+      "d1:d2:d3 = 1.0 : 0.707 : 0.577\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h1=1\n",
+    "k1=0\n",
+    "l1=0\n",
+    "h2=1\n",
+    "k2=1\n",
+    "l2=0\n",
+    "h3=1\n",
+    "k3=1\n",
+    "l3=1\n",
+    "a=1\n",
+    "\n",
+    "#Calculations\n",
+    "d1=a/(math.sqrt(h1**2+k1**2+l1**2))\n",
+    "d2=a/(math.sqrt(h2**2+k2**2+l2**2))\n",
+    "d3=a/(math.sqrt(h3**2+k3**2+l3**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d1 =\",d1 \n",
+    "print\"d2 =\",round(d2,3)\n",
+    "print\"d3 =\",round(d3,3)\n",
+    "print\"d1:d2:d3 =\",d1,\":\",round(d2,3),\":\",round(d3,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.4, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d(220) = 159.1 pm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "a=450\n",
+    "\n",
+    "#Calculations\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d(220) =\",round(d,1),\"pm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.5, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.615 Angstroms\n",
+      "d = 2.087 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.615\n",
+    "r=1.278\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*r)/math.sqrt(2)\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,3),\"Angstroms\"\n",
+    "print\"d =\",round(d,3),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.7, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 1.45 *10**-10 m\n",
+      "a = 4.1 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=1\n",
+    "lamda=1.54\n",
+    "theta=32*math.pi/180\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda*10**-10)/(2*math.sin(theta))   #derived from 2dsin(theta)=n*l\n",
+    "a=d*(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Results\n",
+    "print\"d =\",round(d*10**10,2),\"*10**-10 m\"\n",
+    "print\"a =\",round(a*10**10,1),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.8, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 50,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i.  d/n = 2.582 Angstroms\n",
+      "ii. d/n = 1.824 Angstroms\n",
+      "iii.d/n = 1.289 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta1=6.45*math.pi/180\n",
+    "theta2=9.15*math.pi/180\n",
+    "theta3=13*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "dbyn1=lamda/(2*(math.sin(theta1)))\n",
+    "dbyn2=lamda/(2*math.sin(theta2))\n",
+    "dbyn3=lamda/(2*math.sin(theta3))\n",
+    "           \n",
+    "#Results\n",
+    "print\"i.  d/n =\",round(dbyn1,3),\"Angstroms\"\n",
+    "print\"ii. d/n =\",round(dbyn2,3),\"Angstroms\"\n",
+    "print\"iii.d/n =\",round(dbyn3,3),\"Angstroms\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.9, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "n = 1.53\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1.18\n",
+    "theta=90*math.pi/180\n",
+    "lamda=1.540\n",
+    "\n",
+    "#Calculations\n",
+    "n=(2*d*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"n =\",round(n,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.10, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.51 Angstorms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta=9.5*math.pi/180\n",
+    "n=1\n",
+    "d=0.5           #d200=a/math.sqrt(2**2+0**2+0**2)=0.5a\n",
+    "#Calculations\n",
+    "a=n*lamda/(2*d*math.sin(theta))     #2*d*sin(theta)=n*lamda \n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstorms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.11, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sin(theta3) = 26 35.9387574495\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.842\n",
+    "n1=1\n",
+    "q=(8+(35/60))*(math.pi/180)\n",
+    "n2=3\n",
+    "d=1\n",
+    "#Calculations\n",
+    "#n*lamda=2*d*sin(theta)\n",
+    "#n1*0.842=2*d*sin(q)\n",
+    "#n3*0.842=2*d*sin(theta3)\n",
+    "#Dividing both the eauations, we get\n",
+    "#(n2*lamda)/(n1*lamda)=2*d*math.sin(theta3)/2*d*math.sin(q)\n",
+    "theta3=math.asin((((n2*lamda)/(n1*lamda))*(2*d*math.sin(q)))/(2*d))\n",
+    "d=theta3*180/math.pi;\n",
+    "a_d=int(d);\n",
+    "a_m=(d-int(d))*60\n",
+    "\n",
+    "#Result\n",
+    "print\"sin(theta3) =\",a_d,a_m\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.12, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.22 Angstorms\n",
+      "sqrt(h**2+k**2+l**2) = 1.424\n",
+      "Therefore, h**2+k**2+l**2 =sqrt(2)\n",
+      "h =1, k=1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.16\n",
+    "lamda=1.54\n",
+    "n=1\n",
+    "theta=20.3*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda)/(2*math.sin(theta))\n",
+    "x=a/d                             #let math.sqrt(h**2+k**2+l**2)=x\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sqrt(h**2+k**2+l**2) =\",round(x,3)\n",
+    "print\"Therefore, h**2+k**2+l**2 =sqrt(2)\"\n",
+    "print\"h =1, k=1\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.13, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 4.09 Angstroms\n",
+      "d = 2.36 Angstroms\n",
+      "lamda = 1.552 Angstroms\n",
+      "E = 8.0 *10**3 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "## importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=4\n",
+    "A=107.87\n",
+    "rho=10500\n",
+    "N=6.02*10**26\n",
+    "h=1;\n",
+    "k=1;\n",
+    "l=1;\n",
+    "H=6.625*10**-34\n",
+    "e=1.6*10**-19\n",
+    "theta=(19+(12/60))*math.pi/180\n",
+    "C=3*10**8\n",
+    "#Calculations\n",
+    "a=((n*A)/(rho*N))**(1/3)*10**10\n",
+    "d=a/math.sqrt(h**2+k**2+l**2)\n",
+    "lamda=2*d*math.sin(theta)\n",
+    "E=(H*C)/(lamda*10**-10*e)\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstroms\"\n",
+    "print\"d =\",round(d,2),\"Angstroms\"\n",
+    "print\"lamda =\",round(lamda,3),\"Angstroms\"\n",
+    "print\"E =\",round(E/10**3),\"*10**3 eV\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.14, Page number 7.19"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 72,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.64 Angstorms\n",
+      "sin(theta)= 0.288\n",
+      "X = 7.554 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=4.57\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "lamda=1.52\n",
+    "twotheta=33.5*math.pi/180\n",
+    "r=5                  #radius\n",
+    "#Calculations\n",
+    "d=a/(h**2+k**2+l**2)**(1/2)\n",
+    "sintheta=lamda/(2*d)\n",
+    "X=r/math.tan(twotheta)\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sin(theta)=\",round(sintheta,3)\n",
+    "print\"X =\",round(X,3),\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS IN SOLIDS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS IN SOLIDS.ipynb
new file mode 100644
index 00000000..09325a4b
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS IN SOLIDS.ipynb
@@ -0,0 +1,215 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#8:Defects In Solids "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.1, Page number 8.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "at 0K, The number of vacancies per kilomole of copper is 0\n",
+      "at 300K, The number of vacancies per kilomole of copper is 7.577 *10**5\n",
+      "at 900K, The numb ber of vacancies per kilomole of copper is 6.502 *10**19\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**26\n",
+    "deltaHv=120\n",
+    "B=1.38*10**-23\n",
+    "k=6.023*10**23\n",
+    "\n",
+    "#Calculations\n",
+    "n0=0                                          # 0 in denominator\n",
+    "n300=N*math.exp(-deltaHv*10**3/(k*B*300))     #The number of vacancies per kilomole of copper\n",
+    "n900=N*math.exp(-(deltaHv*10**3)/(k*B*900))\n",
+    "\n",
+    "#Results\n",
+    "print\"at 0K, The number of vacancies per kilomole of copper is\",n0\n",
+    "print\"at 300K, The number of vacancies per kilomole of copper is\",round(n300/10**5,3),\"*10**5\"\n",
+    "print\"at 900K, The numb ber of vacancies per kilomole of copper is\",round(n900/10**19,3),\"*10**19\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.2, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fraction of vacancies at 1000 degrees C = 8.5 *10**-7\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "F_500=1*10**-10\n",
+    "delta_Hv=Symbol('delta_Hv')\n",
+    "k=Symbol('k')\n",
+    "T1=500+273\n",
+    "T2=1000+273\n",
+    "\n",
+    "\n",
+    "#Calculations\n",
+    "lnx=math.log(F_500)*T1/T2;\n",
+    "x=math.exp(round(lnx,2))\n",
+    "\n",
+    "print\"Fraction of vacancies at 1000 degrees C =\",round(x*10**7,1),\"*10**-7\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.3, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of unit cell of NaCl = 1.794 *10**-28 m**3\n",
+      "Total number of ion pairs 'N' =' 2.23 *10**28\n",
+      "The concentration of Schottky defects per m**3 at 300K = 6.42 *10**11\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=(2*2.82*10**-10)\n",
+    "delta_Hs=1.971*1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=300\n",
+    "\n",
+    "#Calculations\n",
+    "V=a**3                           #Volume of unit cell of NaCl\n",
+    "N=4/V                            #Total number of ion pairs\n",
+    "n=N*math.e**-(delta_Hs/(2*k*T))  \n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of unit cell of NaCl =\",round(V*10**28,3),\"*10**-28 m**3\"\n",
+    "print\"Total number of ion pairs 'N' ='\",round(N/10**28,2),\"*10**28\"\n",
+    "print\"The concentration of Schottky defects per m**3 at 300K =\",round(n/10**11,2),\"*10**11\"\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.4, Page number 8.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The number that must be created on heating from 0 to 500K is n= 9.22 *10**12 per cm**3\n",
+      "As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\n",
+      "The amount of climb down by the dislocation is 0.369 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**23\n",
+    "delta_Hv=1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=500\n",
+    "mv=5.55;     #molar volume\n",
+    "x=2*10**-8;     #numbber of cm in 1 angstrom\n",
+    "\n",
+    "#Calculations\n",
+    "n=N*math.exp(-delta_Hv/(k*T))/mv\n",
+    "a=round(n/(5*10**7*10**6),4)*x;\n",
+    "\n",
+    "#Result\n",
+    "print\"The number that must be created on heating from 0 to 500K is n=\",round(n/10**12,2),\"*10**12 per cm**3\" #into cm**3\n",
+    "print\"As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\"\n",
+    "print\"The amount of climb down by the dislocation is\",a*10**8,\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS.ipynb
new file mode 100644
index 00000000..09325a4b
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS.ipynb
@@ -0,0 +1,215 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#8:Defects In Solids "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.1, Page number 8.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "at 0K, The number of vacancies per kilomole of copper is 0\n",
+      "at 300K, The number of vacancies per kilomole of copper is 7.577 *10**5\n",
+      "at 900K, The numb ber of vacancies per kilomole of copper is 6.502 *10**19\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**26\n",
+    "deltaHv=120\n",
+    "B=1.38*10**-23\n",
+    "k=6.023*10**23\n",
+    "\n",
+    "#Calculations\n",
+    "n0=0                                          # 0 in denominator\n",
+    "n300=N*math.exp(-deltaHv*10**3/(k*B*300))     #The number of vacancies per kilomole of copper\n",
+    "n900=N*math.exp(-(deltaHv*10**3)/(k*B*900))\n",
+    "\n",
+    "#Results\n",
+    "print\"at 0K, The number of vacancies per kilomole of copper is\",n0\n",
+    "print\"at 300K, The number of vacancies per kilomole of copper is\",round(n300/10**5,3),\"*10**5\"\n",
+    "print\"at 900K, The numb ber of vacancies per kilomole of copper is\",round(n900/10**19,3),\"*10**19\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.2, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fraction of vacancies at 1000 degrees C = 8.5 *10**-7\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "F_500=1*10**-10\n",
+    "delta_Hv=Symbol('delta_Hv')\n",
+    "k=Symbol('k')\n",
+    "T1=500+273\n",
+    "T2=1000+273\n",
+    "\n",
+    "\n",
+    "#Calculations\n",
+    "lnx=math.log(F_500)*T1/T2;\n",
+    "x=math.exp(round(lnx,2))\n",
+    "\n",
+    "print\"Fraction of vacancies at 1000 degrees C =\",round(x*10**7,1),\"*10**-7\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.3, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of unit cell of NaCl = 1.794 *10**-28 m**3\n",
+      "Total number of ion pairs 'N' =' 2.23 *10**28\n",
+      "The concentration of Schottky defects per m**3 at 300K = 6.42 *10**11\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=(2*2.82*10**-10)\n",
+    "delta_Hs=1.971*1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=300\n",
+    "\n",
+    "#Calculations\n",
+    "V=a**3                           #Volume of unit cell of NaCl\n",
+    "N=4/V                            #Total number of ion pairs\n",
+    "n=N*math.e**-(delta_Hs/(2*k*T))  \n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of unit cell of NaCl =\",round(V*10**28,3),\"*10**-28 m**3\"\n",
+    "print\"Total number of ion pairs 'N' ='\",round(N/10**28,2),\"*10**28\"\n",
+    "print\"The concentration of Schottky defects per m**3 at 300K =\",round(n/10**11,2),\"*10**11\"\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.4, Page number 8.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The number that must be created on heating from 0 to 500K is n= 9.22 *10**12 per cm**3\n",
+      "As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\n",
+      "The amount of climb down by the dislocation is 0.369 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**23\n",
+    "delta_Hv=1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=500\n",
+    "mv=5.55;     #molar volume\n",
+    "x=2*10**-8;     #numbber of cm in 1 angstrom\n",
+    "\n",
+    "#Calculations\n",
+    "n=N*math.exp(-delta_Hv/(k*T))/mv\n",
+    "a=round(n/(5*10**7*10**6),4)*x;\n",
+    "\n",
+    "#Result\n",
+    "print\"The number that must be created on heating from 0 to 500K is n=\",round(n/10**12,2),\"*10**12 per cm**3\" #into cm**3\n",
+    "print\"As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\"\n",
+    "print\"The amount of climb down by the dislocation is\",a*10**8,\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS_1.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS_1.ipynb
new file mode 100644
index 00000000..09325a4b
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/8.DEFECTS_IN_SOLIDS_1.ipynb
@@ -0,0 +1,215 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#8:Defects In Solids "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.1, Page number 8.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "at 0K, The number of vacancies per kilomole of copper is 0\n",
+      "at 300K, The number of vacancies per kilomole of copper is 7.577 *10**5\n",
+      "at 900K, The numb ber of vacancies per kilomole of copper is 6.502 *10**19\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**26\n",
+    "deltaHv=120\n",
+    "B=1.38*10**-23\n",
+    "k=6.023*10**23\n",
+    "\n",
+    "#Calculations\n",
+    "n0=0                                          # 0 in denominator\n",
+    "n300=N*math.exp(-deltaHv*10**3/(k*B*300))     #The number of vacancies per kilomole of copper\n",
+    "n900=N*math.exp(-(deltaHv*10**3)/(k*B*900))\n",
+    "\n",
+    "#Results\n",
+    "print\"at 0K, The number of vacancies per kilomole of copper is\",n0\n",
+    "print\"at 300K, The number of vacancies per kilomole of copper is\",round(n300/10**5,3),\"*10**5\"\n",
+    "print\"at 900K, The numb ber of vacancies per kilomole of copper is\",round(n900/10**19,3),\"*10**19\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.2, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fraction of vacancies at 1000 degrees C = 8.5 *10**-7\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "F_500=1*10**-10\n",
+    "delta_Hv=Symbol('delta_Hv')\n",
+    "k=Symbol('k')\n",
+    "T1=500+273\n",
+    "T2=1000+273\n",
+    "\n",
+    "\n",
+    "#Calculations\n",
+    "lnx=math.log(F_500)*T1/T2;\n",
+    "x=math.exp(round(lnx,2))\n",
+    "\n",
+    "print\"Fraction of vacancies at 1000 degrees C =\",round(x*10**7,1),\"*10**-7\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.3, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of unit cell of NaCl = 1.794 *10**-28 m**3\n",
+      "Total number of ion pairs 'N' =' 2.23 *10**28\n",
+      "The concentration of Schottky defects per m**3 at 300K = 6.42 *10**11\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=(2*2.82*10**-10)\n",
+    "delta_Hs=1.971*1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=300\n",
+    "\n",
+    "#Calculations\n",
+    "V=a**3                           #Volume of unit cell of NaCl\n",
+    "N=4/V                            #Total number of ion pairs\n",
+    "n=N*math.e**-(delta_Hs/(2*k*T))  \n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of unit cell of NaCl =\",round(V*10**28,3),\"*10**-28 m**3\"\n",
+    "print\"Total number of ion pairs 'N' ='\",round(N/10**28,2),\"*10**28\"\n",
+    "print\"The concentration of Schottky defects per m**3 at 300K =\",round(n/10**11,2),\"*10**11\"\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.4, Page number 8.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The number that must be created on heating from 0 to 500K is n= 9.22 *10**12 per cm**3\n",
+      "As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\n",
+      "The amount of climb down by the dislocation is 0.369 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**23\n",
+    "delta_Hv=1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=500\n",
+    "mv=5.55;     #molar volume\n",
+    "x=2*10**-8;     #numbber of cm in 1 angstrom\n",
+    "\n",
+    "#Calculations\n",
+    "n=N*math.exp(-delta_Hv/(k*T))/mv\n",
+    "a=round(n/(5*10**7*10**6),4)*x;\n",
+    "\n",
+    "#Result\n",
+    "print\"The number that must be created on heating from 0 to 500K is n=\",round(n/10**12,2),\"*10**12 per cm**3\" #into cm**3\n",
+    "print\"As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\"\n",
+    "print\"The amount of climb down by the dislocation is\",a*10**8,\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter01.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter01.ipynb
new file mode 100644
index 00000000..7c7516bf
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter01.ipynb
@@ -0,0 +1,630 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 1:INTERFERENCE AND DIFFRACTION OF LIGHT"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.1, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The fringe width beta= 0.2945 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "D=1                    #Distance in metre\n",
+    "lamda=589*10**-9       #nm to metres\n",
+    "d=2*10**-3             #mm to metre\n",
+    "\n",
+    "#Calculation\n",
+    "beta=(D*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"The fringe width beta=\",round(beta*10**3,4),\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.2, Page number 1.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness of glass plate= 3.27 micron.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=3               #position\n",
+    "lamda=5450*10**-10      #Wawelength in Armstrong to metre\n",
+    "mu=1.5\n",
+    "\n",
+    "#Calculation\n",
+    "t=(N*lamda)/(mu-1)\n",
+    "\n",
+    "#Result\n",
+    "print\"Thickness of glass plate=\",round(t*10**6,2),\"micron.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.3, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total number of lines n the grating= 9539.0\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "w=0.02      \n",
+    "n=1\n",
+    "lamda=6.56*10**-7\n",
+    "theta=(18+(14/60))*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "N=(w*math.sin(theta))/(n*lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"Total number of lines n the grating=\",round(N)\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.4, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "t= 11.786 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893*10**-10           #Angstroms to mts\n",
+    "x=4*10**-2\n",
+    "beta=1*10**-3\n",
+    "\n",
+    "#Calculation\n",
+    "t=(lamda*x)/(2*beta)\n",
+    "\n",
+    "#Result\n",
+    "print\"t=\",round(t*10**6,3),\"micron\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.6, Page number 1.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The minimum thickness of coating,t= 996.4 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5500\n",
+    "nf=1.38\n",
+    "\n",
+    "#Calculation\n",
+    "t=lamda/(4*nf)\n",
+    "\n",
+    "#Result\n",
+    "print\"The minimum thickness of coating,t=\",round(t,1),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.7, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelength,lamda= 5448.0 *10**-10 m\n",
+      "#Answer varies due to rounding of number\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "beta=0.00227     #distance between adjascent green lines\n",
+    "D=2.5             \n",
+    "d=0.0006        #distance between narrow slits\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(beta*d)/D\n",
+    "\n",
+    "#Result\n",
+    "print\"Wavelength,lamda=\",round(lamda*10**10),\"*10**-10 m\"\n",
+    "print\"#Answer varies due to rounding of number\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.8, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest thickness of plate,t= 3927.0 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5890*10**-10\n",
+    "mu=1.5\n",
+    "theta=60*math.pi/180     #Converting in to degrees\n",
+    "\n",
+    "#Calculation\n",
+    "cos=math.cos(theta)\n",
+    "t=(lamda)/(2*mu*(math.cos(theta)))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Smallest thickness of plate,t=\",round(t*10**10),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.9, Page number 1.37"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index,mu = 1.31\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "R=1\n",
+    "n=5\n",
+    "lamda=5.895*10**-7\n",
+    "dn=0.003\n",
+    "\n",
+    "#Calculation\n",
+    "mu=(4*R*n*lamda)/(dn**2)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index,mu =\",mu "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.10, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 327.4\n",
+      "The number of rulings needed is 328. This is the minimum requirement.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5893;\n",
+    "n=3\n",
+    "d_lamda=6\n",
+    "\n",
+    "#Calculation\n",
+    "N=(lamda)/(n*d_lamda)\n",
+    "\n",
+    "#Result\n",
+    "print\"N =\",round(N,1)\n",
+    "print\"The number of rulings needed is 328. This is the minimum requirement.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": false
+   },
+   "source": [
+    "##Example number 1.11, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Smallest angular separation of two stars = 2.642 *10**-7 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5.5*10**-7\n",
+    "d=2.54\n",
+    "x=1.22\n",
+    "#Calculation\n",
+    "dtheta=(x*lamda)/d\n",
+    "\n",
+    "#Result\n",
+    "print\"Smallest angular separation of two stars =\",round(dtheta*10**7,3),\"*10**-7 radian\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 1.12, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Slit width value, a= 13000.0 Angstroms = 1.3 micron\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6500\n",
+    "theta=30*math.pi/180\n",
+    "\n",
+    "#Calculation\n",
+    "a=lamda/math.sin(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Slit width value, a=\",a,\"Angstroms =\",round(a*10**-4,1),\"micron\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.13, Page number 1.38"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "r= 2.0 /1\n",
+      "Hence the ratio of the amplitudes= 2:1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a2=1\n",
+    "a1=2*a2\n",
+    "#Calculation\n",
+    "r=a1/a2\n",
+    "\n",
+    "#Result\n",
+    "print\"r=\",r,\"/1\"   #r = r/1 = r:1\n",
+    "print\"Hence the ratio of the amplitudes= 2:1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.14, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 73,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 2.0 *10**-4 m = 0.2 mm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=5*10**-3/2\n",
+    "lamda=5*10**-7\n",
+    "\n",
+    "#Calculation\n",
+    "a=(lamda)/theta\n",
+    "\n",
+    "print\"a=\",round(a*10**4),\"*10**-4 m\",\"=\",a*10**3,\"mm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.15, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 76,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "mu-1= 0.4\n",
+      "Refractive index, mu= 1.4\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=20\n",
+    "lamda=5000*10**-10       #Angstroms to meters\n",
+    "t=2.5*10**-5\n",
+    "\n",
+    "#Calculation\n",
+    "mu_1=(N*lamda)/t\n",
+    "mu=1+(mu_1)\n",
+    "\n",
+    "#Result\n",
+    "print\"mu-1=\",mu_1\n",
+    "print\"Refractive index, mu=\",mu"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 1.16, Page number 1.39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 79,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Maximum number of orders= 3.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=90*math.pi/180    #theta=90 degrees to get maximum number of orders assume\n",
+    "lamda=5890*10**-10\n",
+    "aplusb=2*10**-6       #micro mts to mts \n",
+    "\n",
+    "#Calculation\n",
+    "n=(aplusb*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"Maximum number of orders=\",round(n)\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter02.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter02.ipynb
new file mode 100644
index 00000000..d548c39e
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter02.ipynb
@@ -0,0 +1,426 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 2:POLARIZATION AND ULTRASONICS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.1, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "theta= 45.0 degrees\n",
+      "theta= 135.0 degrees\n",
+      "#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "I=1/2\n",
+    "\n",
+    "#Calculation\n",
+    "theta1=math.acos(1/math.sqrt(2))*(180/math.pi)\n",
+    "theta2=math.acos(-1/math.sqrt(2))*(180/math.pi)\n",
+    "#Result\n",
+    "print\"theta=\",theta1,\"degrees\"\n",
+    "print\"theta=\",theta2,\"degrees\"\n",
+    "print\"#The value of theta can be +(or)- 45 degrees and +(or)-135 degrees.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.2, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ip= 60.0 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Calculation\n",
+    "ip=math.atan(1.732)*(180/math.pi)\n",
+    "\n",
+    "#Result\n",
+    "print\"ip=\",round(ip),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.3, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "phi= 104.7 rad.\n",
+      "Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1*10**-3\n",
+    "lamda=6000*10**-10\n",
+    "nd=0.01                  #difference between the refractive indices(n1 - n2)\n",
+    "\n",
+    "#Calculation\n",
+    "phi=(2*math.pi*d*nd)/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"phi=\",round(phi,1),\"rad.\"\n",
+    "print\"Since the phase difference should be with in 2pi radius, we get phi=4.169 rad.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.4, Page number 2.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Thickness,t= 27.47 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=5000*10**-10\n",
+    "mu_0=1.5533\n",
+    "mu_1=1.5442\n",
+    "\n",
+    "#Calculations\n",
+    "t=lamda/(2*(mu_0 - mu_1))\n",
+    "         \n",
+    "#Result\n",
+    "print\"Thickness,t=\",round(t*10**6,2),\"micro m.\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.5, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Birefringence of the crystal delta/mu= 0.005\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=6000*10**-10\n",
+    "t=0.003*10**-2\n",
+    "\n",
+    "#Calculations\n",
+    "delta_mu=lamda/(4*t)\n",
+    "\n",
+    "#Result\n",
+    "print\"Birefringence of the crystal delta/mu=\",delta_mu\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.6, Page number 2.34¶"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Refractive index of medium= 1.732\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "theta=60*(math.pi/180)        #When the angle of refraction is 30degrees, angle of reflection will be 60degrees\n",
+    "\n",
+    "#Calculation\n",
+    "mu=math.tan(theta)\n",
+    "\n",
+    "#Result\n",
+    "print\"Refractive index of medium=\",round(mu,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.7, Page number 2.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Ultrasonic wavelength,lamda s = 7.47 *10**-4 m\n",
+      "Velocity of ultrasonic waves in liquid = 1495.0 ms**-1\n",
+      "#Answer varies due to rounding of numbers\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "m=1\n",
+    "lamda_l=6000*10**-10\n",
+    "theta=0.046*(math.pi/180)\n",
+    "n=2*10**6\n",
+    "\n",
+    "#Calculation\n",
+    "lamda_s=(m*lamda_l)/(math.sin(theta))\n",
+    "v=n*lamda_s\n",
+    "\n",
+    "#Result\n",
+    "print\"Ultrasonic wavelength,lamda s =\",round(lamda_s*10**4,2),\"*10**-4 m\"\n",
+    "print\"Velocity of ultrasonic waves in liquid =\",round(v),\"ms**-1\"\n",
+    "print\"#Answer varies due to rounding of numbers\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 2.8, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Velocity of blood flow = 0.1001 m s**-1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "C=1500\n",
+    "Df=267\n",
+    "f=2*10**6\n",
+    "theta=0*math.pi/180          #degrees\n",
+    "\n",
+    "#Calculation\n",
+    "V=(C*Df)/(2*f*math.cos(theta))\n",
+    "\n",
+    "#Result\n",
+    "print\"Velocity of blood flow =\",round(V,4),\"m s**-1\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.9, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fundamental frequency,f = 4.0 *10**6 Hz.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "t=0.7*10**-3\n",
+    "E=8.8*10**10\n",
+    "rho=2800\n",
+    "\n",
+    "#Calculation\n",
+    "f=(1/(2*t))*math.sqrt(E/rho)       #Fundamental frequency\n",
+    "\n",
+    "#Result\n",
+    "print\"Fundamental frequency,f =\",round(f*10**-6),\"*10**6 Hz.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 2.10, Page number 2.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The depth of the sea = 997.5 m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "v=1500\n",
+    "t=1.33\n",
+    "\n",
+    "#Calculation\n",
+    "d=(v*t)/2\n",
+    "\n",
+    "#Result\n",
+    "print\"The depth of the sea =\",d,\"m.\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter03.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter03.ipynb
new file mode 100644
index 00000000..a665a220
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter03.ipynb
@@ -0,0 +1,472 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#3: ACOUSTICS OF BUILDINGS AND SUPERCONDUCTIVITY"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.1, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Reverbration time = 3.9 s\n",
+      "Final Reverbration time = 1.95 s\n",
+      "Thus the reverbration time is reduced to one-half of its initial value\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=2265\n",
+    "A=92.9\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "\n",
+    "#Result\n",
+    "print\"Reverbration time =\",round(T,1),\"s\"\n",
+    "print\"Final Reverbration time =\",round(T2,2),\"s\"\n",
+    "print\"Thus the reverbration time is reduced to one-half of its initial value\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.2, Page number 3.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of the hall = 2160 m**3\n",
+      "Total absorption = 430.7 m**2\n",
+      "Reverbration time = 0.8 second\n",
+      "Answer given for the Reverbration time in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a1=450    #Area of plastered wall\n",
+    "a2=360    #Area of wooden floor and wooden doors\n",
+    "a3=24     #Area of Glass\n",
+    "a4=600    #Area of seats\n",
+    "a5=500    #Area of audience when they are in seats\n",
+    "c1=0.03   #Coefficient of absorption of plastered wall\n",
+    "c2=0.06   #Coefficient of absorption of wooden floor and wooden doors\n",
+    "c3=0.025   #Coefficient of absorption of Glass\n",
+    "c4=0.3    #Coefficient of absorption of seats\n",
+    "c5=0.43   #Coefficient of absorption of audience when they are in seats\n",
+    "l=12\n",
+    "b=30\n",
+    "h=6\n",
+    "\n",
+    "#Calculation\n",
+    "V=l*b*h        #volume of the hall\n",
+    "A=(a1*c1)+(a2*c2)+(a3*c3)+(a4*c4)+(a5*c5)  #Total absorption\n",
+    "T=(0.16*V)/A   #Reverbration time\n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of the hall =\",V,\"m**3\"\n",
+    "print\"Total absorption =\",A,\"m**2\"\n",
+    "print\"Reverbration time =\",round(T,1),\"second\"\n",
+    "print\"Answer given for the Reverbration time in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.3, Page number 3.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total absorpttion = 1000.0  m**2 of O.W.U.\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "T=1.2\n",
+    "V=7500\n",
+    "\n",
+    "#Calculation\n",
+    "A=(0.16*V)/T\n",
+    "\n",
+    "#Result\n",
+    "print\"Total absorpttion =\",A,\" m**2 of O.W.U.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.4, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "T1 = 1.45 second\n",
+      "T2 = 0.73 second\n",
+      "Change in Reverbration time = 0.727 second\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "V=12*10**4\n",
+    "A=13200\n",
+    "x=2               #The absorption become 2*A of open window\n",
+    "\n",
+    "#Calculation\n",
+    "T1=(0.16*V)/A      #Sabine's formula  \n",
+    "T2=(0.16*V)/(x*A)\n",
+    "Td=T1-T2\n",
+    "\n",
+    "#Result\n",
+    "print\"T1 =\",round(T1,2),\"second\"\n",
+    "print\"T2 =\",round(T2,2),\"second\"\n",
+    "print\"Change in Reverbration time =\",round(Td,3),\"second\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.6, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "critical field is 33.64 *10**3 ampere/m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=64*10**3;    #initial field(ampere/m)\n",
+    "T=5;    #temperature(K)\n",
+    "Tc=7.26;   #transition temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "H=H0*(1-(T/Tc)**2);     #critical field(ampere/m)\n",
+    "\n",
+    "#Result\n",
+    "print \"critical field is\",round(H/10**3,2),\"*10**3 ampere/m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.7, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency of generated microwaves= 483.0 *10**9 Hz\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19\n",
+    "V=1*10\n",
+    "h=6.625*10**-34\n",
+    "\n",
+    "#Calculations\n",
+    "v=(2*e*V**-3)/h \n",
+    "\n",
+    "#Result\n",
+    "print\"Frequency of generated microwaves=\",round(v/10**9),\"*10**9 Hz\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.8, Page number 3.34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of electrons per unit volume = 3.7 *10**28/m**3\n",
+      "Effective mass of electron 'm*' = 17.3 *10*-31 kg\n",
+      "Penetration depth = 3.81011659367 Angstroms\n",
+      "#The answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=7300                  #density in (kg/m**3)\n",
+    "N=6.02*10**26           #Avagadro Number\n",
+    "A=118.7                 #Atomic Weight\n",
+    "E=1.9                 #Effective mass\n",
+    "e=1.6*10**-19\n",
+    "\n",
+    "#Calculations\n",
+    "n=(d*N)/A\n",
+    "m=E*9.1*10**-31\n",
+    "x=4*math.pi*10**-7*n*e**2\n",
+    "lamda_L=math.sqrt(m/x)\n",
+    "      \n",
+    "#Result\n",
+    "print \"Number of electrons per unit volume =\",round(n/10**28,1),\"*10**28/m**3\"\n",
+    "print\"Effective mass of electron 'm*' =\",round(m*10**31,1),\"*10*-31 kg\"\n",
+    "print\"Penetration depth =\",lamda_L*10**8,\"Angstroms\"\n",
+    "print\"#The answer given in the text book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "##Example number 3.9, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Tc = 7.0969 K\n",
+      "lamda0= 39.0 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda_L1=39.6*10**-9\n",
+    "lamda_L2=173*10**-9\n",
+    "T1=7.1\n",
+    "T2=3\n",
+    "\n",
+    "#Calculations\n",
+    "x=(lamda_L1/lamda_L2)**2\n",
+    "Tc4=(T1**4)-((T2**4)*x)/(1-x)\n",
+    "Tc=(Tc4)**(1/4)\n",
+    "print\"Tc =\",round(Tc,4),\"K\"\n",
+    "print\"lamda0=\",round((math.sqrt(1-(T2/Tc)**4)*lamda_L1)*10**9),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.10, Page number 3.35"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hc = 4.2759 *10**4\n",
+      "Critical current density,Jc = 1.71 *10**8 ampere/metre**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "H0=6.5*10**4           #(ampere/metre)\n",
+    "T=4.2                  #K\n",
+    "Tc=7.18                #K\n",
+    "r=0.5*10**-3\n",
+    "\n",
+    "#Calculations\n",
+    "Hc=H0*(1-(T/Tc)**2)\n",
+    "Ic=(2*math.pi*r)*Hc\n",
+    "A=math.pi*r**2\n",
+    "Jc=Ic/A                #Critical current density\n",
+    "\n",
+    "#Result\n",
+    "print\"Hc =\",round(Hc/10**4,4),\"*10**4\"\n",
+    "print \"Critical current density,Jc =\",round(Jc/10**8,2),\"*10**8 ampere/metre**2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 3.11, Page number 6.36"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "New critical temperature for mercury = 4.145 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "Tc1=4.185\n",
+    "M1=199.5\n",
+    "M2=203.4\n",
+    "\n",
+    "#Calculations\n",
+    "Tc2=Tc1*(M1/M2)**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print\"New critical temperature for mercury =\",round(Tc2,3),\"K\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter04.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter04.ipynb
new file mode 100644
index 00000000..823230a1
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter04.ipynb
@@ -0,0 +1,236 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Chapter 4:LASERS "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.1, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Divergence = 0.5 *10**-3 radian\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1 = 2;                #in radians\n",
+    "r2 = 3;                #in radians\n",
+    "d1 = 4;                #Converting from mm to radians\n",
+    "d2 = 6;                #Converting from mm to radians\n",
+    "\n",
+    "#calculations\n",
+    "D = (r2-r1)/(d2*10**3-d1*10**3)   #Divergence\n",
+    "\n",
+    "#Result\n",
+    "print \"Divergence =\",round(D*10**3,3),\"*10**-3 radian\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.2, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frequency (V) = 4.32 *10**14 Hz\n",
+      "Relative Population= 1.081 *10**30\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                    #The speed of light\n",
+    "Lamda=6943                   #Wavelength\n",
+    "T=300                        #Temperature in Kelvin\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "k=1.38*10**-23               #Boltzmann's constant\n",
+    "\n",
+    "#Calculations\n",
+    "\n",
+    "V=(C)/(Lamda*10**-10)       #Frequency\n",
+    "R=math.exp(h*V/(k*T))       #Relative population\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency (V) =\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"Relative Population=\",round(R/10**30,3),\"*10**30\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.3, Page number 4.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Frequency= 4.74 *10**14 Hz\n",
+      "no.of photons emitted= 7.322 *10**15 photons/sec\n",
+      "Power density = 2.3 kWm**-2\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "C=3*10**8                     #Velocity of light\n",
+    "W=632.8*10**-9                #wavelength\n",
+    "P=2.3\n",
+    "t=1\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "S=1*10**-6\n",
+    "\n",
+    "#Calculations\n",
+    "V=C/W                        #Frequency\n",
+    "n=((P*10**-3)*t)/(h*V)       #no.of photons emitted\n",
+    "PD=P*10**-3/S                #Power density\n",
+    "\n",
+    "#Result\n",
+    "print \"Frequency=\",round(V/10**14,2),\"*10**14 Hz\"\n",
+    "print \"no.of photons emitted=\",round(n/10**15,3),\"*10**15 photons/sec\"\n",
+    "print \"Power density =\",round(PD/1000,1),\"kWm**-2\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.4, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Wavelenght = 8628.0 Angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "h=6.626*10**-34              #Planck constant \n",
+    "C=3*10**8                    #Velocity of light\n",
+    "E_g=1.44                     #bandgap \n",
+    "\n",
+    "#calculations\n",
+    "lamda=(h*C)*10**10/(E_g*1.6*10**-19)       #Wavelenght\n",
+    "\n",
+    "#Result\n",
+    "print \"Wavelenght =\",round(lamda),\"Angstrom\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 4.5, Page number 4.33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Band gap = 0.8 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "W=1.55                       #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "E_g=(1.24)/W                 #Bandgap in eV           \n",
+    "\n",
+    "#Result\n",
+    "print \"Band gap =\",E_g,\"eV\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter05.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter05.ipynb
new file mode 100644
index 00000000..49cd3086
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter05.ipynb
@@ -0,0 +1,651 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 5:Fiber Optics"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.1, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 125,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The Critical angle = 78.5 degrees\n",
+      "The numerical aperture = 0.3\n",
+      "The acceptance angle = 17.4 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.50          #Core refractive index\n",
+    "n2=1.47          #Cladding refractive index\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)        #Critical angle       \n",
+    "N_a=(n1**2-n2**2)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "\n",
+    "#Results\n",
+    "print \"The Critical angle =\",round(C_a*180/math.pi,1),\"degrees\"\n",
+    "print \"The numerical aperture =\",round(N_a,2)\n",
+    "print \"The acceptance angle =\",round(A_a*180/math.pi,1),\"degrees\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.2, Page number 5.28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 126,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "N = 490.0\n",
+      "Fiber can support 490.0 guided modes\n",
+      "In graded index fiber, No.of modes propogated inside the fiber = 245.0 only\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "N_a=0.2             #Numerical aperture\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"N =\",N\n",
+    "print \"Fiber can support\",N,\"guided modes\"\n",
+    "print \"In graded index fiber, No.of modes propogated inside the fiber =\",N/2,\"only\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.3, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.008691\n",
+      "No. of modes that can be propogated = 1.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=50                #diameter\n",
+    "n1=1.450\n",
+    "n2=1.447\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "N=4.9*(((d*10**-6*N_a)/(lamda*10**-6))**2)\n",
+    "\n",
+    "#Results\n",
+    "print \"Numerical aperture =\",N_a\n",
+    "print \"No. of modes that can be propogated =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.4, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.46\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "delta=0.05          \n",
+    "n1=1.46\n",
+    "\n",
+    "#Calculation\n",
+    "N_a=n1*(2*delta)**(1/2)     #Numerical aperture\n",
+    "\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.5, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "V number = 94.72\n",
+      "maximum no.of modes propogating through fiber = 4486.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=50\n",
+    "n1=1.53\n",
+    "n2=1.50\n",
+    "lamda=1             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=(n1**2-n2**2)   #Numerical aperture\n",
+    "V=((2*math.pi*a)/lamda)*N_a**(1/2)\n",
+    "\n",
+    "#Result\n",
+    "print \"V number =\",round(V,2)\n",
+    "print \"maximum no.of modes propogating through fiber =\",round(N)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.6, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 64,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Number of modes = 24589.0 modes\n",
+      "No.of modes is doubled to account for the two possible polarisations\n",
+      "Total No.of modes = 49178.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "a=100\n",
+    "N_a=0.3               #Numerical aperture\n",
+    "lamda=850             #wavelength\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=(2*(math.pi)**2*a**2*10**-12*N_a**2)/lamda**2*10**-18\n",
+    "#Result\n",
+    "print \"Number of modes =\",round(V_n/10**-36),\"modes\"\n",
+    "print \"No.of modes is doubled to account for the two possible polarisations\"\n",
+    "print \"Total No.of modes =\",round(V_n/10**-36)*2\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.7, Page number 5.29"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 88,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Cutoff Wavellength = 1.315 micro m.\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "a=5;\n",
+    "n1=1.48;\n",
+    "delta=0.01;\n",
+    "V=25;\n",
+    "\n",
+    "#Calculation\n",
+    "lamda=(math.pi*(a*10**-6)*n1*math.sqrt(2*delta))/V   # Cutoff Wavelength\n",
+    "\n",
+    "#Result\n",
+    "print \"Cutoff Wavellength =\",round(lamda*10**7,3),\"micro m.\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.8, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 87,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Maximum core radius= 9.95 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "V=2.405\n",
+    "lamda=1.3\n",
+    "N_a=0.05\n",
+    "\n",
+    "#Calculations\n",
+    "a_max=(V*lamda)/(2*math.pi*N_a)\n",
+    "\n",
+    "#Result\n",
+    "print \"Maximum core radius=\",round(a_max,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.9, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Acceptance angle, theta_a = 17.46 degrees\n",
+      "For skew rays,theta_as  34.83 degrees\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "N_a=0.3\n",
+    "gamma=45\n",
+    "\n",
+    "#Calculations\n",
+    "theta_a=math.asin(N_a)\n",
+    "theta_as=math.asin((N_a)/math.cos(gamma))\n",
+    "\n",
+    "#Results\n",
+    "print \"Acceptance angle, theta_a =\",round(theta_a*180/math.pi,2),\"degrees\"\n",
+    "print \"For skew rays,theta_as \",round(theta_as*180/math.pi,2),\"degrees\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.10, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 115,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Numerical aperture = 0.303\n",
+      "Acceptance angle = 17.63 degrees\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.53\n",
+    "delta=0.0196\n",
+    "\n",
+    "#Calculations\n",
+    "N_a=n1*(2*delta)**(1/2)\n",
+    "A_a=math.asin(N_a)\n",
+    "#Result\n",
+    "print \"Numerical aperture =\",round(N_a,3)\n",
+    "print \"Acceptance angle =\",round(A_a*180/math.pi,2),\"degrees\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.11, Page number 5.30"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "delta = 0.01\n",
+      "Core radius,a = 1.55 micro m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.480\n",
+    "n2=1.465\n",
+    "V=2.405\n",
+    "lamda=850*10**-9\n",
+    "\n",
+    "#Calculations\n",
+    "delta=(n1**2-n2**2)/(2*n1**2)\n",
+    "a=(V*lamda*10**-9)/(2*math.pi*n1*math.sqrt(2*delta))\n",
+    "\n",
+    "#Results\n",
+    "print \"delta =\",round(delta,2)\n",
+    "print \"Core radius,a =\",round(a*10**15,2),\"micro m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.12, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 147,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " Critical angle= 83.38 degrees\n",
+      "Fiber length covered in one reflection= 430.84 micro m\n",
+      "Total no.of reflections per metre= 2321.0\n",
+      "Since L=1m, Total dist. travelled by light over one metre of fiber = 1.0067 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n1=1.5\n",
+    "n2=1.49\n",
+    "a=25\n",
+    "\n",
+    "#Calculations\n",
+    "C_a=math.asin(n2/n1)           #Critical angle\n",
+    "L=2*a*math.tan(C_a)             \n",
+    "N_r=10**6/L                    \n",
+    "\n",
+    "#Result\n",
+    "print \"Critical angle=\",round(C_a*180/math.pi,2),\"degrees\"\n",
+    "print \"Fiber length covered in one reflection=\",round(L,2),\"micro m\"\n",
+    "print \"Total no.of reflections per metre=\",round(N_r)\n",
+    "print \"Since L=1m, Total dist. travelled by light over one metre of fiber =\",round(1/math.sin(C_a),4),\"m\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.13, Page number 5.31"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 155,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "No.of modes = 154.69 =155(approx)\n",
+      "Taking the two possible polarizations, Total No.of nodes = 309.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "alpha=1.85\n",
+    "lamda=1.3*10**-6\n",
+    "a=25*10**-6\n",
+    "N_a=0.21\n",
+    "\n",
+    "#Calculations\n",
+    "V_n=((2*math.pi**2)*a**2*N_a**2)/lamda**2\n",
+    "N_m=(alpha/(alpha+2))*V_n\n",
+    "\n",
+    "print \"No.of modes =\",round(N_m,2),\"=155(approx)\"\n",
+    "print \"Taking the two possible polarizations, Total No.of nodes =\",round(N_m*2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.14, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a)Signal attention per unit length = 3.9 dB km**-1\n",
+      "b)Overall signal attenuation = 39.0 dB\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "P_i=100\n",
+    "P_o=2\n",
+    "L=10\n",
+    "\n",
+    "#Calculations\n",
+    "S=(10/L)*math.log(P_i/P_o)\n",
+    "O=S*L\n",
+    "\n",
+    "#Result\n",
+    "print \"a)Signal attention per unit length =\",round(S,1),\"dB km**-1\"\n",
+    "print \"b)Overall signal attenuation =\",round(O),\"dB\"\n",
+    "print \"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example 5.15, Page number 5.32"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Total dispersion = 1343.3 ns\n",
+      "Bandwidth length product = 37.22 Hz-km\n",
+      "#Answer given in the text book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "L=10\n",
+    "n1=1.55\n",
+    "delta=0.026\n",
+    "C=3*10**5\n",
+    "\n",
+    "#Calculations\n",
+    "delta_T=(L*n1*delta)/C\n",
+    "B_W=10/(2*delta_T)\n",
+    "\n",
+    "#Result\n",
+    "print \"Total dispersion =\",round(delta_T/10**-9,1),\"ns\"\n",
+    "print \"Bandwidth length product =\",round(B_W/10**5,2),\"Hz-km\"\n",
+    "print \"#Answer given in the text book is wrong\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter06.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter06.ipynb
new file mode 100644
index 00000000..392de89d
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter06.ipynb
@@ -0,0 +1,555 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#Chapter 6:Magnetic Properties and Crystal Structures"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.1, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "temperature rise is 8.43 K\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "El=10**-2*50;      #energy loss(J)\n",
+    "H=El*60;           #heat produced(J)\n",
+    "d=7.7*10**3;       #iron rod(kg/m**3)\n",
+    "s=0.462*10**-3;    #specific heat(J/kg K)\n",
+    "\n",
+    "#Calculation\n",
+    "theta=H/(d*s);     #temperature rise(K)\n",
+    "\n",
+    "#Result\n",
+    "print \"temperature rise is\",round(theta,2),\"K\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.2, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "magnetic field at the centre is 14.0 weber/m**2\n",
+      "dipole moment is 9.0 *10**-24 ampere/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "e=1.6*10**-19;    #charge(coulomb)\n",
+    "new=6.8*10**15;   #frequency(revolutions per second)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "R=5.1*10**-11;     #radius(m)\n",
+    "\n",
+    "#Calculation\n",
+    "i=round(e*new,4);          #current(ampere)\n",
+    "B=mew0*i/(2*R);            #magnetic field at the centre(weber/m**2)\n",
+    "A=math.pi*R**2;\n",
+    "d=i*A;                    #dipole moment(ampere/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"magnetic field at the centre is\",round(B),\"weber/m**2\"\n",
+    "print \"dipole moment is\",round(d*10**24),\"*10**-24 ampere/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.3, Page number 6.46"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "intensity of magnetisation is 5.0 ampere/m\n",
+      "flux density in material is 1.257 weber/m**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "chi=0.5*10**-5;    #magnetic susceptibility\n",
+    "H=10**6;     #field strength(ampere/m)\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "\n",
+    "#Calculation\n",
+    "I=chi*H;     #intensity of magnetisation(ampere/m)\n",
+    "B=mew0*(I+H);    #flux density in material(weber/m**2)\n",
+    "\n",
+    "#Result\n",
+    "print \"intensity of magnetisation is\",I,\"ampere/m\"\n",
+    "print \"flux density in material is\",round(B,3),\"weber/m**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.4, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of Bohr magnetons is 2.22 bohr magneon/atom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "B=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "a=2.86*10**-10;      #edge(m)\n",
+    "Is=1.76*10**6;       #saturation value of magnetisation(ampere/m)\n",
+    "\n",
+    "#Calculation\n",
+    "N=2/a**3;\n",
+    "mew_bar=Is/N;      #number of Bohr magnetons(ampere m**2)\n",
+    "mew_bar=mew_bar/B;      #number of Bohr magnetons(bohr magneon/atom)\n",
+    "\n",
+    "#Result\n",
+    "print \"number of Bohr magnetons is\",round(mew_bar,2),\"bohr magneon/atom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.5, Page number 6.47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "average magnetic moment is 2.79 *10**-3 bohr magneton/spin\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "mew0=4*math.pi*10**-7;\n",
+    "H=9.27*10**-24;      #bohr magneton(ampere m**2)\n",
+    "beta=10**6;      #field(ampere/m)\n",
+    "k=1.38*10**-23;    #boltzmann constant\n",
+    "T=303;    #temperature(K)\n",
+    "\n",
+    "#Calculation\n",
+    "mm=mew0*H*beta/(k*T);    #average magnetic moment(bohr magneton/spin)\n",
+    "\n",
+    "#Result\n",
+    "print \"average magnetic moment is\",round(mm*10**3,2),\"*10**-3 bohr magneton/spin\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.6, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hysteresis loss per cycle is 188.0 J/m**3\n",
+      "hysteresis loss per second is 9400.0 watt/m**3\n",
+      "power loss is 1.23 watt/kg\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "A=94;      #area(m**2)\n",
+    "vy=0.1;    #value of length(weber/m**2)\n",
+    "vx=20;     #value of unit length\n",
+    "n=50;      #number of magnetization cycles\n",
+    "d=7650;    #density(kg/m**3)\n",
+    "\n",
+    "#Calculation\n",
+    "h=A*vy*vx;     #hysteresis loss per cycle(J/m**3)\n",
+    "hs=h*n;       #hysteresis loss per second(watt/m**3)\n",
+    "pl=hs/d;      #power loss(watt/kg)\n",
+    "\n",
+    "#Result\n",
+    "print \"hysteresis loss per cycle is\",h,\"J/m**3\"\n",
+    "print \"hysteresis loss per second is\",hs,\"watt/m**3\"\n",
+    "print \"power loss is\",round(pl,2),\"watt/kg\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.7, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 5.43 Angstorm\n",
+      "density = 6.88 kg/m**3\n",
+      "#Answer given in the textbook is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "d=2.351                 #bond lenght\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "n=8                     #number of atoms in unit cell\n",
+    "A=28.09                 #Atomin mass of silicon\n",
+    "m=6.02*10**26           #1mole\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*d)/math.sqrt(3)\n",
+    "p=(n*A)/((a*10**-10)*m)    #density\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a,2),\"Angstorm\"\n",
+    "print \"density =\",round(p*10**16,2),\"kg/m**3\"\n",
+    "print\"#Answer given in the textbook is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.8, Page number 6.48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      " radius of largest sphere is 0.154700538379252*r\n",
+      "maximum radius of sphere is 0.414213562373095*r\n"
+     ]
+    }
+   ],
+   "source": [
+    " import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=Symbol('r')\n",
+    "\n",
+    "#Calculation\n",
+    "a1=4*r/math.sqrt(3);\n",
+    "R1=(a1/2)-r;           #radius of largest sphere\n",
+    "a2=4*r/math.sqrt(2);\n",
+    "R2=(a2/2)-r;       #maximum radius of sphere\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of largest sphere is\",R1\n",
+    "print \"maximum radius of sphere is\",R2    "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.9, Page number 6.49"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a1= 2.905 Angstrom\n",
+      "Unit cell volume =a1**3 = 24.521 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.26 *10**-30 m**3\n",
+      "a2= 3.654 Angstorm\n",
+      "Unit cell volume =a2**3 = 48.8 *10**-30 m**3\n",
+      "Volume occupied by one atom = 12.2 *10**-30 m**3\n",
+      "Volume Change in % = 0.493\n",
+      "Density Change in % = 0.5\n",
+      "Thus the increase of density or the decrease of volume is about 0.5%\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "r1=1.258            #Atomic radius of BCC\n",
+    "r2=1.292            #Atomic radius of FCC\n",
+    "\n",
+    "#calculations\n",
+    "a1=(4*r1)/math.sqrt(3)       #in BCC\n",
+    "b1=((a1)**3)*10**-30         #Unit cell volume\n",
+    "v1=(b1)/2                    #Volume occupied by one atom\n",
+    "a2=2*math.sqrt(2)*r2         #in FCC\n",
+    "b2=(a2)**3*10**-30           #Unit cell volume\n",
+    "v2=(b2)/4                    #Volume occupied by one atom  \n",
+    "v_c=((v1)-(v2))*100/(v1)     #Volume Change in % \n",
+    "d_c=((v1)-(v2))*100/(v2)     #Density Change in %\n",
+    "\n",
+    "#Results\n",
+    "print \"a1=\",round(a1,3),\"Angstrom\" \n",
+    "print \"Unit cell volume =a1**3 =\",round((b1)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v1/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"a2=\",round(a2,3),\"Angstorm\"\n",
+    "print \"Unit cell volume =a2**3 =\",round((b2)/10**-30,3),\"*10**-30 m**3\"\n",
+    "print \"Volume occupied by one atom =\",round(v2/10**-30,2),\"*10**-30 m**3\"\n",
+    "print \"Volume Change in % =\",round(v_c,3)\n",
+    "print \"Density Change in % =\",round(d_c,2)\n",
+    "print \"Thus the increase of density or the decrease of volume is about 0.5%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.10, Page number 6.50"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a= 0.563 *10**-9 metre\n",
+      "spacing between the nearest neighbouring ions = 0.2814 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "M=58.5                  #Molecular wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=2180                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*M)/(N*rho))**(1/3)    \n",
+    "s=a/2\n",
+    "\n",
+    "#Result\n",
+    "print \"a=\",round(a/10**-9,3),\"*10**-9 metre\"\n",
+    "print \"spacing between the nearest neighbouring ions =\",round(s/10**-9,4),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.11, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant, a= 0.36 nm\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#variable declaration\n",
+    "n=4     \n",
+    "A=63.55                 #Atomic wt. of NaCl\n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "rho=8930                #density\n",
+    "\n",
+    "#Calculations\n",
+    "a=((n*A)/(N*rho))**(1/3)      #Lattice Constant\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant, a=\",round(a*10**9,2),\"nm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 6.12, Page number 6.51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Density of iron = 8805.0 kg/m**-3\n"
+     ]
+    }
+   ],
+   "source": [
+    "import math\n",
+    "\n",
+    "#variable declaration\n",
+    "r=0.123                  #Atomic radius\n",
+    "n=4\n",
+    "A=55.8                   #Atomic wt\n",
+    "a=2*math.sqrt(2) \n",
+    "N=6.02*10**26           #Avagadro number\n",
+    "\n",
+    "#Calculations\n",
+    "rho=(n*A)/((a*r*10**-9)**3*N)\n",
+    "\n",
+    "#Result\n",
+    "print \"Density of iron =\",round(rho),\"kg/m**-3\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter07.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter07.ipynb
new file mode 100644
index 00000000..884fa904
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter07.ipynb
@@ -0,0 +1,615 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#7: Crystal Planes and X-ray Diffraction"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.1, Page number 7.12"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Number of atoms per unit area of (100)plane= 1/(4*R**2)\n",
+      "ii)Number of atoms per unit area of (110)plane= 2.82842712474619*R**2\n",
+      "iii)Number of atoms per unit area of (111)plane= 2.3094010767585*R**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "#Variable declaration\n",
+    "R=Symbol('R')\n",
+    "a=2*R\n",
+    "\n",
+    "#Results\n",
+    "print\"i)Number of atoms per unit area of (100)plane=\",1/a**2\n",
+    "print\"ii)Number of atoms per unit area of (110)plane=\",1/math.sqrt(2)*a**2\n",
+    "print\"iii)Number of atoms per unit area of (111)plane=\",1/math.sqrt(3)*a**2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.2, Page number 7.13"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i)Surface area of the face ABCD = 13.0 *10**-14 mm**2\n",
+      "ii)Surface area of plane (110) = 1.09 *10**13 atoms/mm**2\n",
+      "iii)Surface area of pane(111)= 1.772 *10**13 atoms/mm**2\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.61*10**-7\n",
+    "BC=math.sqrt(2)/2\n",
+    "AD=(math.sqrt(6))/2\n",
+    "#Result\n",
+    "print\"i)Surface area of the face ABCD =\",round(a**2*10**14),\"*10**-14 mm**2\"\n",
+    "print\"ii)Surface area of plane (110) =\",round((2/(a*math.sqrt(2)*a)/10**13),2),\"*10**13 atoms/mm**2\"\n",
+    "print\"iii)Surface area of pane(111)=\",round(2/(BC*AD*a**2)*10**-13,3),\"*10**13 atoms/mm**2\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.3, Page number 7.14"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d1 = 1.0\n",
+      "d2 = 0.707\n",
+      "d3 = 0.577\n",
+      "d1:d2:d3 = 1.0 : 0.707 : 0.577\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h1=1\n",
+    "k1=0\n",
+    "l1=0\n",
+    "h2=1\n",
+    "k2=1\n",
+    "l2=0\n",
+    "h3=1\n",
+    "k3=1\n",
+    "l3=1\n",
+    "a=1\n",
+    "\n",
+    "#Calculations\n",
+    "d1=a/(math.sqrt(h1**2+k1**2+l1**2))\n",
+    "d2=a/(math.sqrt(h2**2+k2**2+l2**2))\n",
+    "d3=a/(math.sqrt(h3**2+k3**2+l3**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d1 =\",d1 \n",
+    "print\"d2 =\",round(d2,3)\n",
+    "print\"d3 =\",round(d3,3)\n",
+    "print\"d1:d2:d3 =\",d1,\":\",round(d2,3),\":\",round(d3,3)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.4, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d(220) = 159.1 pm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "a=450\n",
+    "\n",
+    "#Calculations\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"d(220) =\",round(d,1),\"pm\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.5, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 49,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.615 Angstroms\n",
+      "d = 2.087 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.615\n",
+    "r=1.278\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "\n",
+    "#Calculations\n",
+    "a=(4*r)/math.sqrt(2)\n",
+    "d=a/(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,3),\"Angstroms\"\n",
+    "print\"d =\",round(d,3),\"Angstroms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.7, Page number 7.15"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 1.45 *10**-10 m\n",
+      "a = 4.1 *10**-10 m\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=1\n",
+    "lamda=1.54\n",
+    "theta=32*math.pi/180\n",
+    "h=2\n",
+    "k=2\n",
+    "l=0\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda*10**-10)/(2*math.sin(theta))   #derived from 2dsin(theta)=n*l\n",
+    "a=d*(math.sqrt(h**2+k**2+l**2))\n",
+    "\n",
+    "#Results\n",
+    "print\"d =\",round(d*10**10,2),\"*10**-10 m\"\n",
+    "print\"a =\",round(a*10**10,1),\"*10**-10 m\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.8, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 50,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "i.  d/n = 2.582 Angstroms\n",
+      "ii. d/n = 1.824 Angstroms\n",
+      "iii.d/n = 1.289 Angstroms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta1=6.45*math.pi/180\n",
+    "theta2=9.15*math.pi/180\n",
+    "theta3=13*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "dbyn1=lamda/(2*(math.sin(theta1)))\n",
+    "dbyn2=lamda/(2*math.sin(theta2))\n",
+    "dbyn3=lamda/(2*math.sin(theta3))\n",
+    "           \n",
+    "#Results\n",
+    "print\"i.  d/n =\",round(dbyn1,3),\"Angstroms\"\n",
+    "print\"ii. d/n =\",round(dbyn2,3),\"Angstroms\"\n",
+    "print\"iii.d/n =\",round(dbyn3,3),\"Angstroms\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.9, Page number 7.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "n = 1.53\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "d=1.18\n",
+    "theta=90*math.pi/180\n",
+    "lamda=1.540\n",
+    "\n",
+    "#Calculations\n",
+    "n=(2*d*math.sin(theta))/lamda\n",
+    "\n",
+    "#Result\n",
+    "print\"n =\",round(n,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.10, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 3.51 Angstorms\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.58\n",
+    "theta=9.5*math.pi/180\n",
+    "n=1\n",
+    "d=0.5           #d200=a/math.sqrt(2**2+0**2+0**2)=0.5a\n",
+    "#Calculations\n",
+    "a=n*lamda/(2*d*math.sin(theta))     #2*d*sin(theta)=n*lamda \n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstorms\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.11, Page number 7.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sin(theta3) = 26 35.9387574495\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "lamda=0.842\n",
+    "n1=1\n",
+    "q=(8+(35/60))*(math.pi/180)\n",
+    "n2=3\n",
+    "d=1\n",
+    "#Calculations\n",
+    "#n*lamda=2*d*sin(theta)\n",
+    "#n1*0.842=2*d*sin(q)\n",
+    "#n3*0.842=2*d*sin(theta3)\n",
+    "#Dividing both the eauations, we get\n",
+    "#(n2*lamda)/(n1*lamda)=2*d*math.sin(theta3)/2*d*math.sin(q)\n",
+    "theta3=math.asin((((n2*lamda)/(n1*lamda))*(2*d*math.sin(q)))/(2*d))\n",
+    "d=theta3*180/math.pi;\n",
+    "a_d=int(d);\n",
+    "a_m=(d-int(d))*60\n",
+    "\n",
+    "#Result\n",
+    "print\"sin(theta3) =\",a_d,a_m\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.12, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.22 Angstorms\n",
+      "sqrt(h**2+k**2+l**2) = 1.424\n",
+      "Therefore, h**2+k**2+l**2 =sqrt(2)\n",
+      "h =1, k=1\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=3.16\n",
+    "lamda=1.54\n",
+    "n=1\n",
+    "theta=20.3*math.pi/180\n",
+    "\n",
+    "#Calculations\n",
+    "d=(n*lamda)/(2*math.sin(theta))\n",
+    "x=a/d                             #let math.sqrt(h**2+k**2+l**2)=x\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sqrt(h**2+k**2+l**2) =\",round(x,3)\n",
+    "print\"Therefore, h**2+k**2+l**2 =sqrt(2)\"\n",
+    "print\"h =1, k=1\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.13, Page number 7.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a = 4.09 Angstroms\n",
+      "d = 2.36 Angstroms\n",
+      "lamda = 1.552 Angstroms\n",
+      "E = 8.0 *10**3 eV\n"
+     ]
+    }
+   ],
+   "source": [
+    "## importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "n=4\n",
+    "A=107.87\n",
+    "rho=10500\n",
+    "N=6.02*10**26\n",
+    "h=1;\n",
+    "k=1;\n",
+    "l=1;\n",
+    "H=6.625*10**-34\n",
+    "e=1.6*10**-19\n",
+    "theta=(19+(12/60))*math.pi/180\n",
+    "C=3*10**8\n",
+    "#Calculations\n",
+    "a=((n*A)/(rho*N))**(1/3)*10**10\n",
+    "d=a/math.sqrt(h**2+k**2+l**2)\n",
+    "lamda=2*d*math.sin(theta)\n",
+    "E=(H*C)/(lamda*10**-10*e)\n",
+    "\n",
+    "#Result\n",
+    "print\"a =\",round(a,2),\"Angstroms\"\n",
+    "print\"d =\",round(d,2),\"Angstroms\"\n",
+    "print\"lamda =\",round(lamda,3),\"Angstroms\"\n",
+    "print\"E =\",round(E/10**3),\"*10**3 eV\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 7.14, Page number 7.19"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 72,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d = 2.64 Angstorms\n",
+      "sin(theta)= 0.288\n",
+      "X = 7.554 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=4.57\n",
+    "h=1\n",
+    "k=1\n",
+    "l=1\n",
+    "lamda=1.52\n",
+    "twotheta=33.5*math.pi/180\n",
+    "r=5                  #radius\n",
+    "#Calculations\n",
+    "d=a/(h**2+k**2+l**2)**(1/2)\n",
+    "sintheta=lamda/(2*d)\n",
+    "X=r/math.tan(twotheta)\n",
+    "\n",
+    "#Result\n",
+    "print\"d =\",round(d,2),\"Angstorms\"\n",
+    "print\"sin(theta)=\",round(sintheta,3)\n",
+    "print\"X =\",round(X,3),\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter08.ipynb b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter08.ipynb
new file mode 100644
index 00000000..09325a4b
--- /dev/null
+++ b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Chapter08.ipynb
@@ -0,0 +1,215 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#8:Defects In Solids "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.1, Page number 8.16"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "at 0K, The number of vacancies per kilomole of copper is 0\n",
+      "at 300K, The number of vacancies per kilomole of copper is 7.577 *10**5\n",
+      "at 900K, The numb ber of vacancies per kilomole of copper is 6.502 *10**19\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**26\n",
+    "deltaHv=120\n",
+    "B=1.38*10**-23\n",
+    "k=6.023*10**23\n",
+    "\n",
+    "#Calculations\n",
+    "n0=0                                          # 0 in denominator\n",
+    "n300=N*math.exp(-deltaHv*10**3/(k*B*300))     #The number of vacancies per kilomole of copper\n",
+    "n900=N*math.exp(-(deltaHv*10**3)/(k*B*900))\n",
+    "\n",
+    "#Results\n",
+    "print\"at 0K, The number of vacancies per kilomole of copper is\",n0\n",
+    "print\"at 300K, The number of vacancies per kilomole of copper is\",round(n300/10**5,3),\"*10**5\"\n",
+    "print\"at 900K, The numb ber of vacancies per kilomole of copper is\",round(n900/10**19,3),\"*10**19\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.2, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Fraction of vacancies at 1000 degrees C = 8.5 *10**-7\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from sympy import Symbol\n",
+    "\n",
+    "#Variable declaration\n",
+    "F_500=1*10**-10\n",
+    "delta_Hv=Symbol('delta_Hv')\n",
+    "k=Symbol('k')\n",
+    "T1=500+273\n",
+    "T2=1000+273\n",
+    "\n",
+    "\n",
+    "#Calculations\n",
+    "lnx=math.log(F_500)*T1/T2;\n",
+    "x=math.exp(round(lnx,2))\n",
+    "\n",
+    "print\"Fraction of vacancies at 1000 degrees C =\",round(x*10**7,1),\"*10**-7\" "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.3, Page number 8.17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Volume of unit cell of NaCl = 1.794 *10**-28 m**3\n",
+      "Total number of ion pairs 'N' =' 2.23 *10**28\n",
+      "The concentration of Schottky defects per m**3 at 300K = 6.42 *10**11\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=(2*2.82*10**-10)\n",
+    "delta_Hs=1.971*1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=300\n",
+    "\n",
+    "#Calculations\n",
+    "V=a**3                           #Volume of unit cell of NaCl\n",
+    "N=4/V                            #Total number of ion pairs\n",
+    "n=N*math.e**-(delta_Hs/(2*k*T))  \n",
+    "\n",
+    "#Result\n",
+    "print\"Volume of unit cell of NaCl =\",round(V*10**28,3),\"*10**-28 m**3\"\n",
+    "print\"Total number of ion pairs 'N' ='\",round(N/10**28,2),\"*10**28\"\n",
+    "print\"The concentration of Schottky defects per m**3 at 300K =\",round(n/10**11,2),\"*10**11\"\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##Example number 8.4, Page number 8.18"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "The number that must be created on heating from 0 to 500K is n= 9.22 *10**12 per cm**3\n",
+      "As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\n",
+      "The amount of climb down by the dislocation is 0.369 cm\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "N=6.023*10**23\n",
+    "delta_Hv=1.6*10**-19\n",
+    "k=1.38*10**-23\n",
+    "T=500\n",
+    "mv=5.55;     #molar volume\n",
+    "x=2*10**-8;     #numbber of cm in 1 angstrom\n",
+    "\n",
+    "#Calculations\n",
+    "n=N*math.exp(-delta_Hv/(k*T))/mv\n",
+    "a=round(n/(5*10**7*10**6),4)*x;\n",
+    "\n",
+    "#Result\n",
+    "print\"The number that must be created on heating from 0 to 500K is n=\",round(n/10**12,2),\"*10**12 per cm**3\" #into cm**3\n",
+    "print\"As one step is 2 Angstorms, 5*10**7 vacancies are required for 1cm\"\n",
+    "print\"The amount of climb down by the dislocation is\",a*10**8,\"cm\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Eng.Physics by M.Arumugam.zip b/ENGINEERING_PHYSICS_by_M.ARUMUGAM/Eng.Physics by M.Arumugam.zip
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