{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 14: Dielectrics" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.1, Page 475" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import pi\n", "\n", "#Variable declaration\n", "er=1.0000684;#dielectric constant of helium \n", "N=2.7*1e25;#atoms/m^3\n", "\n", "#Calculations\n", "r=(er-1)/(4*pi*N);\n", "R=r**(1./3); #radius of electron cloud\n", "\n", "#Result\n", "print 'radius of electron cloud is %.1f*10^-10 m'%(R/1e-10)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "radius of electron cloud is 0.6*10^-10 m\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.2, Page 475" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "k=1.38*1e-23;#boltzmann constant\n", "N=1e27;#HCL molecule per cubic meter\n", "E=1e6;#electric field of vapour\n", "D=3.33*1e-30;\n", "\n", "#Calculations\n", "pHCL=1.04*D;\n", "T=300;#tempreture in kelvin\n", "alpha=(pHCL)**2/(3*k*T);\n", "p0=N*alpha*E;#orientation polarization\n", "\n", "#Result\n", "print 'orientation polarization is %.3f*10^-6 C/m^2'%(p0/1e-6)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "orientation polarization is 0.966*10^-6 C/m^2\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.3, Page 476" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "alpha=0.35*1e-40;#polarizability of gas\n", "N=2.7*1e25;\n", "e0=8.854*1e-12;#permittivity of vacume\n", "\n", "#Calculation\n", "er=1+(N*alpha/e0);#relative permittivity\n", "\n", "#Result\n", "print 'relative permittivity is %.6f'%er\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "relative permittivity is 1.000107\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.4, Page 480" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "er=12.;#relative permittivity\n", "N=5*1e28;#atoms/m^3\n", "e0=8.854*1e-12;#permittivity of vacume\n", "\n", "#Calculations\n", "x=(er-1)/(er+2);\n", "alpha=(3*e0/N)*x;#electrical polarizability\n", "\n", "#Result\n", "print 'electronic polarizability = %.2f*10^-40 F*m^2'%(alpha/1e-40)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "electronic polarizability = 4.17*10^-40 F*m^2\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.5, Page 483" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import atan,degrees\n", "\n", "#Variable declaration\n", "C=2.4*1e-12;#given capacitance in F\n", "e0=8.854*1e-12;#permittivity of vacume\n", "a=4*1e-4;#area in m^2\n", "d=0.5*1e-2;#thickness\n", "tandelta=0.02;\n", "\n", "#Calculations&Results\n", "er=(C*d)/(e0*a);#relative permittivity\n", "print 'relative permittivity = %.2f'%er\n", "lf=er*tandelta;#loss factor\n", "print 'electric loss factor = %.4f'%lf\n", "delta=degrees(atan(tandelta))\n", "PA=90-delta;#phase angle\n", "print 'phase angle = %.2f degrees'%PA\n", "#incorrect answers in the textbook\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "relative permittivity = 3.39\n", "electric loss factor = 0.0678\n", "phase angle = 88.85 degrees\n" ] } ], "prompt_number": 25 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 14.6, Page 483" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "er=8.;#relative permittivity\n", "a=0.036;#area in m^2\n", "e0=8.854*1e-12;#permittivity of vacume\n", "C=6*1e-6;#capacitance in F\n", "V=15.0;#potential difference\n", "\n", "#Calculations\n", "d=(e0*er*a)/C;\n", "E=V/d;#field strength\n", "\n", "#Results\n", "print 'field strength is= %.3f*10^7 V/m'%(E/1e+7)\n", "dpm=e0*(er-1)*E;#dipole moment/unit volume\n", "print 'dipole moment/unit volume= %.4f*10^-2 C/m^2'%(dpm/1e-2)\n", "#Incorrect answers in the textbook\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "field strength is= 3.529*10^7 V/m\n", "dipole moment/unit volume= 0.2187*10^-2 C/m^2\n" ] } ], "prompt_number": 6 } ], "metadata": {} } ] }