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{
"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": {}
}
]
}
|
