Added(A)/Deleted(D) following books

 A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch11_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch12_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch15_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch16_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch1_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch3_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch5_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch6_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch7_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch8_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/Ch9_1.ipynb
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/screenshots/ConGruenceEqn.png
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/screenshots/DivisionAlgo.png
A  Discrete_Mathematics_by_S._Lipschutz,_M._Lipson_And_V._H._Patil/screenshots/EuclideanAlgo.png
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch10_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch11_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch12_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch13_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch1_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch2_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch3_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch4_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch5_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch6_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch7_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch8_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/Ch9_1.ipynb
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/screenshots/opNip3_1.png
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/screenshots/opNipV3_1.png
A  Electronic_Devices_And_Circuits_by_B._Kumar_And_S._B._Jain/screenshots/transferChar3_1.png
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter10_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter11_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter12_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter13_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter14_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter1_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter2_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter3_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter4_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter5_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter6_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter8_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter9_1.ipynb
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/screenshots/1_1.png
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/screenshots/2_1.png
A  Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/screenshots/3_1.png
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter10_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter11_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter12_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter13_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter14_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter2_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter3_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter4_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter5_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter6_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter7_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter8_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/Chapter9_1.ipynb
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/screenshots/Ch13AngularDisplacement.png
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/screenshots/Ch13LateralDisplacement.png
A  Fiber_Optics_and_Optoelectronics_by_R._P._Khare/screenshots/Ch13LongitudinalDisplacement.png
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch10_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch11_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch12_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch1_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch2_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch3_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch4_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch5_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch6_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch7_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch8_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/Ch9_1.ipynb
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/screenshots/Ch9MolFracNMolVol_1.png
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/screenshots/Ch9_molarFracNMolVol_1.png
A  Introduction_To_Chemical_Engineering_Thermodynamics_by_G._Halder/screenshots/ch10_consistency_1.png
A  Microwave_engineering__by_D.M.Pozar_/Chapter_10_ACTIVE_MICROWAVE_CIRCUITS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_12_INTRODUCTION_TO_MICROWAVE_SYSTEMS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_1_ELECTROMAGNETIC_THEORY_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_2_TRANSMISSION_LINE_THEORY_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_3_TRANSMISSION_LINE_AND_WAVEGUIDES_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_4_MICROWAVE_NETWORK_ANALYSIS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_5_IMPEDENCE_MATCHING_AND_TUNNING_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_6_MICROWAVE_RESONATORS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_7_POWER_DIVIDERS_DIRECTIONAL_COUPLERS_AND_HYBRIDS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_8_MICROWAVE_FILTERS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/Chapter_9_THEORY_AND_DESIGN_OF_FERRIMAGNETIC_COMPONENTS_1.ipynb
A  Microwave_engineering__by_D.M.Pozar_/screenshots/Screen_Shot_2016-04-19_at_1.59.04_pm.png
A  Microwave_engineering__by_D.M.Pozar_/screenshots/Screen_Shot_2016-04-19_at_1.59.33_pm.png
A  Microwave_engineering__by_D.M.Pozar_/screenshots/Screen_Shot_2016-04-19_at_2.00.38_pm.png
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter11_Control_of_DC_Motors_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter12_Controllers_and_Their_Optimisation_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter13_Choppers_and_Transportation_system_Application_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter15_The_AC_motor_control_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter16_Faults_and_Protection_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter3_Fabrication_and_Thermal_characteristics_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter4_Series_and_Parallel_Connection_of_Thyristors_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter5_Line_Commutated_converters_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter7_Inverter_Circuits_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter8_Harmonic_and_PowerFactor_with_the_converter_system_1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/Chapter_2_The_Device__1_1.ipynb
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/screenshots/11.PNG
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/screenshots/15.PNG
A  Thyristors_Theory_And_Applications_by_R._K._Sugandhi_And_K._K._Sugandhi/screenshots/8.PNG

1 files changed, 1256 insertions, 0 deletions

diff --git a/Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter2_1.ipynb b/Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter2_1.ipynb
new file mode 100644
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+++ b/Engineering_Physics_by_S.L.Gupta,_Sanjeev_Gupta/Chapter2_1.ipynb
@@ -0,0 +1,1256 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# 2: Crystal Structure "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.1, Page number 27"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "volume density is 1249.04 kg/m**3\n",
+      "answer in the book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "M=28;     #atomic weight of Si\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "a=5.3*10**-10;      #lattice constant(m)\n",
+    "n=4;\n",
+    "\n",
+    "#Calculations\n",
+    "V=a**3;          #volume(m**3)\n",
+    "m=M/(N*10**3);           #mass(kg)\n",
+    "rho=n*m/V;       #volume density(kg/m**3)\n",
+    "\n",
+    "#Result\n",
+    "print \"volume density is\",round(rho,2),\"kg/m**3\"\n",
+    "print \"answer in the book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.2, Page number 27"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of atoms per unit cell is 2\n",
+      "the lattice is BCC\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "M=55.85;     #atomic weight\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "a=2.9*10**-8;      #lattice constant(m)\n",
+    "rho=7.87;       #volume density(gm/cc)\n",
+    "\n",
+    "#Calculations\n",
+    "n=rho*N*a**3/M;       #number of atoms per unit cell\n",
+    "\n",
+    "#Result\n",
+    "print \"number of atoms per unit cell is\",int(n)\n",
+    "print \"the lattice is BCC\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.3, Page number 28"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of unit cells is 5.019 *10**22\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "M=120;     #atomic mass\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "n=2;\n",
+    "g=20;       #mass(gm)\n",
+    "\n",
+    "#Calculations\n",
+    "u=n*M/N;     \n",
+    "nu=g/u;       #number of unit cells\n",
+    "\n",
+    "#Result\n",
+    "print \"number of unit cells is\",round(nu/10**22,3),\"*10**22\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.4, Page number 33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "miller indices are ( 2 1 0 )\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from fractions import gcd\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=1;\n",
+    "b=2;\n",
+    "c=float(\"inf\");      #intercepts\n",
+    "\n",
+    "#Calculation\n",
+    "lcm=a*b/gcd(a,b);\n",
+    "h=int(lcm/a);\n",
+    "k=int(lcm/b);\n",
+    "l=int(lcm/c);     #miller indices\n",
+    "\n",
+    "#Result\n",
+    "print \"miller indices are (\",h,k,l,\")\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.5, Page number 33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "miller indices are ( 3 2 1 )\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from fractions import gcd\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=2;\n",
+    "b=3;\n",
+    "c=6;      #intercepts\n",
+    "\n",
+    "#Calculation\n",
+    "lcm_ab=a*b/gcd(a,b);         #lcm of a and b\n",
+    "lcm=lcm_ab*c/gcd(lcm_ab,c);      #lcm of a,b and c\n",
+    "h=int(lcm/a);\n",
+    "k=int(lcm/b);\n",
+    "l=int(lcm/c);     #miller indices\n",
+    "\n",
+    "#Result\n",
+    "print \"miller indices are (\",h,k,l,\")\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.6, Page number 33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "miller indices are ( 3 4 0 )\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from fractions import gcd\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=4;\n",
+    "b=3;\n",
+    "c=float(\"inf\");      #intercepts\n",
+    "\n",
+    "#Calculation\n",
+    "lcm=a*b/gcd(a,b);\n",
+    "h=int(lcm/a);\n",
+    "k=int(lcm/b);\n",
+    "l=int(lcm/c);     #miller indices\n",
+    "\n",
+    "#Result\n",
+    "print \"miller indices are (\",h,k,l,\")\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.7, Page number 33"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ratio of intercepts is 6 -2 3\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from fractions import gcd\n",
+    "\n",
+    "#Variable declaration\n",
+    "h=1;\n",
+    "k=-3;\n",
+    "l=2;     #miller indices\n",
+    "\n",
+    "#Calculation\n",
+    "lcm_hk=h*k/gcd(h,k);         #lcm of h and k\n",
+    "lcm=lcm_hk*l/gcd(lcm_hk,l);      #lcm of h,k and l\n",
+    "l1=int(lcm/h);\n",
+    "l2=int(lcm/k);\n",
+    "l3=int(lcm/l);              #intercepts\n",
+    "\n",
+    "#Result\n",
+    "print \"ratio of intercepts is\",l1,l2,l3"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.8, Page number 34"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 23,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "intercept on Y axis is 1.2 angstrom\n",
+      "intercept on Z axis is 4.0 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "a=1.2;\n",
+    "b=1.8;\n",
+    "c=2.0;       #crystal primitives\n",
+    "x=2;\n",
+    "y=3;\n",
+    "z=1;         #intercepts \n",
+    "h=1.2;       #intercept on X axis\n",
+    "\n",
+    "#Calculations\n",
+    "h1=a/x;\n",
+    "k1=b/y;\n",
+    "l1=c/z;\n",
+    "k=h*h1/k1;      #intercept on Y axis\n",
+    "l=h*l1/h1;      #intercept on Z-axis\n",
+    "\n",
+    "#Result\n",
+    "print \"intercept on Y axis is\",k,\"angstrom\"\n",
+    "print \"intercept on Z axis is\",l,\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.9, Page number 39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "interplanar spacing in 1st plane is 1.762 angstrom\n",
+      "interplanar spacing in 2nd plane is 1.246 angstrom\n",
+      "interplanar spacing in 3rd plane is 2.0347 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "r=1.246;     #atomic radius(angstrom)\n",
+    "h1=2;       #intercept on X axis\n",
+    "k1=0;      #intercept on Y axis\n",
+    "l1=0;      #intercept on Z-axis\n",
+    "h2=2;       #intercept on X axis\n",
+    "k2=2;      #intercept on Y axis\n",
+    "l2=0;      #intercept on Z-axis\n",
+    "h3=1;       #intercept on X axis\n",
+    "k3=1;      #intercept on Y axis\n",
+    "l3=1;      #intercept on Z-axis\n",
+    "\n",
+    "#Calculations\n",
+    "a=2*math.sqrt(2)*r;      #lattice constant\n",
+    "d1=a/math.sqrt(h1**2+k1**2+l1**2);       #interplanar spacing in 1st plane(angstrom)\n",
+    "d2=a/math.sqrt(h2**2+k2**2+l2**2);       #interplanar spacing in 2nd plane(angstrom)\n",
+    "d3=a/math.sqrt(h3**2+k3**2+l3**2);       #interplanar spacing in 3rd plane(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"interplanar spacing in 1st plane is\",round(d1,3),\"angstrom\"\n",
+    "print \"interplanar spacing in 2nd plane is\",d2,\"angstrom\"\n",
+    "print \"interplanar spacing in 3rd plane is\",round(d3,4),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.10, Page number 39"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 32,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "interplanar spacing in 1st plane is a/math.sqrt( 2 ) angstrom\n",
+      "interplanar spacing in 2nd plane is a/math.sqrt( 2 ) angstrom\n",
+      "interplanar spacing in 3rd plane is a/math.sqrt( 6 ) angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration \n",
+    "h1=0;       #intercept on X axis\n",
+    "k1=1;      #intercept on Y axis\n",
+    "l1=1;      #intercept on Z-axis\n",
+    "h2=1;       #intercept on X axis\n",
+    "k2=0;      #intercept on Y axis\n",
+    "l2=1;      #intercept on Z-axis\n",
+    "h3=1;       #intercept on X axis\n",
+    "k3=1;      #intercept on Y axis\n",
+    "l3=2;      #intercept on Z-axis\n",
+    "\n",
+    "#Calculations\n",
+    "d1=h1**2+k1**2+l1**2;       #interplanar spacing in 1st plane(angstrom)\n",
+    "d2=h2**2+k2**2+l2**2;       #interplanar spacing in 2nd plane(angstrom)\n",
+    "d3=h3**2+k3**2+l3**2;       #interplanar spacing in 3rd plane(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"interplanar spacing in 1st plane is a/math.sqrt(\",d1,\") angstrom\"\n",
+    "print \"interplanar spacing in 2nd plane is a/math.sqrt(\",d2,\") angstrom\"\n",
+    "print \"interplanar spacing in 3rd plane is a/math.sqrt(\",d3,\") angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.11, Page number 40"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "interplanar spacing is 1.12 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "a=4.2;      #lattice constant(angstrom)\n",
+    "h=3;       #intercept on X axis\n",
+    "k=2;      #intercept on Y axis\n",
+    "l=1;      #intercept on Z-axis\n",
+    "\n",
+    "#Calculations\n",
+    "d=a/math.sqrt(h**2+k**2+l**2);       #interplanar spacing(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"interplanar spacing is\",round(d,2),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.12, Page number 40"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "miller indices in 1st case are ( 1 1 1 )\n",
+      "miller indices in 2nd case are ( 3 2 1 )\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "from fractions import gcd\n",
+    "\n",
+    "#Variable declaration\n",
+    "a1=1;\n",
+    "b1=1;\n",
+    "c1=1;      #intercepts in 1st case\n",
+    "a2=2;\n",
+    "b2=3;\n",
+    "c2=6;      #intercepts in 2nd case\n",
+    "\n",
+    "#Calculation\n",
+    "lcm_a1b1=a1*b1/gcd(a1,b1);         #lcm of a1 and b1\n",
+    "lcm1=lcm_ab*c1/gcd(lcm_a1b1,c1);      #lcm of a1,b1 and c1\n",
+    "h1=int(lcm1/a1);\n",
+    "k1=int(lcm1/b1);\n",
+    "l1=int(lcm1/c1);     #miller indices in 1st case\n",
+    "lcm_a2b2=a2*b2/gcd(a2,b2);         #lcm of a2 and b2\n",
+    "lcm2=lcm_a2b2*c2/gcd(lcm_a2b2,c2);      #lcm of a2,b2 and c2\n",
+    "h2=int(lcm2/a2);\n",
+    "k2=int(lcm2/b2);\n",
+    "l2=int(lcm2/c2);     #miller indices in 2nd case\n",
+    "\n",
+    "#Result\n",
+    "print \"miller indices in 1st case are (\",h1,k1,l1,\")\"\n",
+    "print \"miller indices in 2nd case are (\",h2,k2,l2,\")\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.14, Page number 47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "density of crystal is 8.929 gm/cm**3\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "M=63.5;     #atomic weight(gm/mol)\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "r=1.278*10**-8;     #atomic radius(cm)\n",
+    "n=4;\n",
+    "\n",
+    "#Calculations\n",
+    "m=M/N;           #mass(g)\n",
+    "a=4*r/math.sqrt(2);      #lattice constant(cm)\n",
+    "V=a**3;          #volume(m**3)\n",
+    "rho=n*m/V;       #density of crystal(g/cm**3)\n",
+    "\n",
+    "#Result\n",
+    "print \"density of crystal is\",round(rho,3),\"gm/cm**3\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.15, Page number 47"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "minimum radius is 0.155 r\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "r=1;     #assume\n",
+    "\n",
+    "#Calculations\n",
+    "a=4*r/math.sqrt(3);      #lattice constant\n",
+    "R=(a-(2*r))/2;           #minimum radius \n",
+    "\n",
+    "#Result\"\n",
+    "print \"minimum radius is\",round(R,3),\"r\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.16, Page number 48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "maximum radius is 0.414 r\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "r=1;     #assume\n",
+    "\n",
+    "#Calculations\n",
+    "a=4*r/math.sqrt(2);      #lattice constant\n",
+    "R=(a/2)-r;           #maximum radius \n",
+    "\n",
+    "#Result\"\n",
+    "print \"maximum radius is\",round(R,3),\"r\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.17, Page number 48"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 44,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "percent volume change is 0.5 %\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "r1=1.258*10**-10;     #atomic radius(m)\n",
+    "r2=1.292*10**-10;     #atomic radius(m)\n",
+    "n1=2;\n",
+    "n2=4;\n",
+    "\n",
+    "#Calculations\n",
+    "a1=4*r1/math.sqrt(3);      #lattice constant(m)\n",
+    "V1=a1**3/n1;          #volume(m**3)\n",
+    "a2=2*math.sqrt(2)*r2;      #lattice constant(m)\n",
+    "V2=a2**3/n2;          #volume(m**3)\n",
+    "V=(V1-V2)*100/V1;           #percent volume change\n",
+    "\n",
+    "#Result\"\n",
+    "print \"percent volume change is\",round(V,1),\"%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.18, Page number 51"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "number of atoms is 1.77 *10**29\n",
+      "density of diamond is 3535.7 kg/m**3\n",
+      "answer in the book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "a=0.356*10**-9;       #cube edge(m)\n",
+    "M=12.01;         #atomic weight\n",
+    "N=6.023*10**26;      #avagadro number\n",
+    "\n",
+    "#Calculations\n",
+    "n=8/a**3;     #number of atoms\n",
+    "m=M/N;        #mass(kg)\n",
+    "rho=m*n;      #density of diamond(kg/m**3)\n",
+    "\n",
+    "#Result\"\n",
+    "print \"number of atoms is\",round(n/10**29,2),\"*10**29\"\n",
+    "print \"density of diamond is\",round(rho,1),\"kg/m**3\"\n",
+    "print \"answer in the book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.19, Page number 54 Theoritical"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.20, Page number 55"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 50,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "volume of unit cell is 9.356 *10**-29 m**3\n",
+      "density of zinc is 6960 kg/m**3\n",
+      "answer in the book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "a=0.27*10**-9;    #lattice constant(m)\n",
+    "c=0.494*10**-9;    #height of cell(m)\n",
+    "M=65.37;         #atomic weight\n",
+    "N=6.023*10**26;      #avagadro number\n",
+    "n=6;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "V=3*math.sqrt(3)*a**2*c/2;      #volume of unit cell(m**3)\n",
+    "rho=n*M/(N*V);    #density of zinc(kg/m**3)\n",
+    "\n",
+    "#Result\"\n",
+    "print \"volume of unit cell is\",round(V*10**29,3),\"*10**-29 m**3\"\n",
+    "print \"density of zinc is\",int(rho),\"kg/m**3\"\n",
+    "print \"answer in the book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.21, Page number 57"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 54,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "density of Si is 2.33 gm/cm**3\n",
+      "density of GaAs is 5.324 gm/cm**3\n",
+      "answer in the book varies due to rounding off errors\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "a1=5.43*10**-8;    #lattice constant(cm)\n",
+    "M1=28.1;         #atomic weight\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "n1=8;     #number of atoms\n",
+    "a2=5.65*10**-8;    #lattice constant(cm)\n",
+    "M2=144.6;         #atomic weight\n",
+    "n2=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "rho1=n1*M1/(N*a1**3);    #density of Si(gm/cm**3)\n",
+    "rho2=n2*M2/(N*a2**3);    #density of GaAs(gm/cm**3)\n",
+    "\n",
+    "#Result\"\n",
+    "print \"density of Si is\",round(rho1,2),\"gm/cm**3\"\n",
+    "print \"density of GaAs is\",round(rho2,3),\"gm/cm**3\"\n",
+    "print \"answer in the book varies due to rounding off errors\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.22, Page number 58"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant is 4 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration    \n",
+    "rho=6250;       #density(kg/m**3)\n",
+    "M=60.2;         #molecular weight\n",
+    "N=6.02*10**26;      #avagadro number\n",
+    "n=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);       #lattice constant(m)\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant is\",int(a*10**10),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.23, Page number 58"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "density of copper is 8938 kg/m**3\n",
+      "answer in the book is wrong\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "r=1.278*10**-8;        #atomic radius(cm)\n",
+    "M=63.54;         #molecular weight\n",
+    "N=6.02*10**23;      #avagadro number\n",
+    "n=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=4*r/math.sqrt(2);       #lattice constant(cm)\n",
+    "rho=n*M*10**3/(N*a**3);       #density(kg/m**3)\n",
+    "\n",
+    "#Result\n",
+    "print \"density of copper is\",int(rho),\"kg/m**3\"\n",
+    "print \"answer in the book is wrong\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.24, Page number 58"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant is 2.867 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "rho=7870;       #density(kg/m**3)\n",
+    "M=55.8;         #molecular weight\n",
+    "N=6.02*10**26;      #avagadro number\n",
+    "n=2;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);      #lattice constant(m)\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant is\",round(a*10**10,3),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.25, Page number 59"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "radius of atom is 1.414 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "rho=6.23;       #density(gm/cc)\n",
+    "M=60;         #molecular weight\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "n=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);      #lattice constant(cm)\n",
+    "r=a*math.sqrt(2)*10**8/4;          #radius of atom(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"radius of atom is\",round(r,3),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.26, Page number 59"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "distance between ions is 3.8 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "rho=2.48;       #density(gm/cc)\n",
+    "M=58;         #molecular weight\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "n=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);      #lattice constant(cm)\n",
+    "r=a*math.sqrt(2)*10**8/4;          #radius of atom(angstrom)\n",
+    "d=2*r;         #distance between ions(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"distance between ions is\",round(d,1),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.27, Page number 59"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "distance between ions is 2.55 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "rho=8.96;       #density(gm/cc)\n",
+    "M=63.5;         #molecular weight\n",
+    "N=6.02*10**23;      #avagadro number\n",
+    "n=4;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);      #lattice constant(cm)\n",
+    "d=a/math.sqrt(2)*10**8;      #distance between ions(angstrom)\n",
+    "\n",
+    "#Result\n",
+    "print \"distance between ions is\",round(d,2),\"angstrom\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.28, Page number 60"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "packing factor is 0.68\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "rho=5.96;       #density(gm/cc)\n",
+    "M=50;         #molecular weight\n",
+    "N=6.023*10**23;      #avagadro number\n",
+    "n=2;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n*M/(rho*N))**(1/3);      #lattice constant(cm)\n",
+    "r=a*math.sqrt(3)/4;          #radius of atom(angstrom)\n",
+    "pf=n*(4/3)*math.pi*r**3/a**3;      #packing factor\n",
+    "\n",
+    "#Result\n",
+    "print \"packing factor is\",round(pf,2)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.29, Page number 61"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "packing fraction is 68 %\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "a=1;     #assume\n",
+    "n=2;     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "r=a*math.sqrt(3)/4;          #radius of atom\n",
+    "V=4*math.pi*r**3/3;          #volume\n",
+    "f=n*V*100/a**3;      #packing fraction\n",
+    "\n",
+    "#Result\n",
+    "print \"packing fraction is\",int(f),\"%\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Example number 2.30, Page number 61"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "lattice constant is 3.22 angstrom\n"
+     ]
+    }
+   ],
+   "source": [
+    "#importing modules\n",
+    "import math\n",
+    "from __future__ import division\n",
+    "\n",
+    "#Variable declaration\n",
+    "Vd=3*10**22;       #density(gm/cc)\n",
+    "n=8*(1/8);     #number of atoms\n",
+    "\n",
+    "#Calculations\n",
+    "a=(n/Vd)**(1/3);      #lattice constant(cm)\n",
+    "\n",
+    "#Result\n",
+    "print \"lattice constant is\",round(a*10**8,2),\"angstrom\""
+   ]
+  }
+ ],
+ "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": "2.7.11"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}