{ "metadata": { "name": "", "signature": "sha256:051dd4d8e63ef61b5430123d8cd0a562c5bdd2cd67fa5b75b947bfd8e0093f34" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter6:ELECTROMAGNETICS" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg1:pg-206" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "r=1 #radius in meter\n", "H=2 #magnitude of field vector in amp/meter\n", "pi=1 #let\n", "I=H*2*pi*r \n", "print\"Current in the wire is %d*pi amp\"%I" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Current in the wire is 4*pi amp\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg5:pg-212" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "sigma=1e-4 #conductivity in siemen/m\n", "Er=2.25 #relative permittivity \n", "E0=1/(4*math.pi*9e9) #permittivity of free space\n", "#E=5e-6*sin(9e9*t) is the electric field in the material volt/m (given)\n", "#J= sigma*E = 1e-4*5e-6*sin(9e9*t)= 5e-10sin(9e9*t)is Conduction current density in A/m**2 \n", "#d(E)/dt= 5e-6*9e9*cos(9e9*t)\n", "#Jd=E0*Er*(d(E)/dt) is Displacement current density in A/m**2\n", "print\"Conduction current density is %s*sin(9e9*t) A/m**2\"%(sigma*5e-6)\n", "print\"Displacement current density is %s*cos(9e9*t) A/m**2\"%round((E0*Er*5e-6*9e9),9)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Conduction current density is 5e-10*sin(9e9*t) A/m**2\n", "Displacement current density is 8.95e-07*cos(9e9*t) A/m**2\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg13:pg-236" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "H0=1 #magnitude of field vector in amp/meter\n", "mu_0=4*round(math.pi,2)*1e-7 #permeability of free space in H/m\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "E0=H0*math.sqrt(mu_0/e0)\n", "print\"Magnitude of electric field for plane wave in free space is \",round(E0,2),\"V/m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Magnitude of electric field for plane wave in free space is 376.72 V/m\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg14:pg-236" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "E0=1e2 #maximum electric field in plane electromagnetic wave in Newton/coul.\n", "c=3e8 #speed of light in m/sec\n", "B0=E0/c \n", "print\"Maximum magnetic field is \",round(B0,9),\"Tesla\"\n", "print\"Maximum magnetic field will be in Z-direction.\"#this part is not printed in answer in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Maximum magnetic field is 3.33e-07 Tesla\n", "Maximum magnetic field will be in Z-direction.\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg15:pg-236" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "S=2*4.2e4/60 #energy flux per unit area per second at the earth surface\n", "mu_0=4*round(math.pi,2)*1e-7 #permeability of free space in H/m\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "EH=S\n", "E_div_H=math.sqrt(mu_0/e0)\n", "E=math.sqrt(E_div_H*EH)\n", "H=EH/E\n", "E0=round(E,1)*round(math.sqrt(2.),3)\n", "H0=H*math.sqrt(2.)\n", "print\"Amplitude of electric field is \",round(E0,1),\"V/m\"\n", "print\"Amplitude of magnetic field is \",round(H0,3),\"A-turn m-1\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Amplitude of electric field is 1026.8 V/m\n", "Amplitude of magnetic field is 2.726 A-turn m-1\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg16:pg-236" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "P0=1000 #power in watt\n", "r=2 #distance in meter\n", "Sav=P0/(4*round(math.pi,2)*r**2)\n", "mu_0=4*round(math.pi,2)*1e-7 #permeability of free space in H/m\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "EH=Sav\n", "E_div_H=math.sqrt(mu_0/e0)\n", "E=math.sqrt(E_div_H*EH)\n", "H=EH/E\n", "print\"Average value of electric field intensity is \",round(E,2),\"V/m\"\n", "print\"Average value of magnetic field intensity is \",round(H,2),\"A-turn m-1\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Average value of electric field intensity is 86.59 V/m\n", "Average value of magnetic field intensity is 0.23 A-turn m-1\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg17:pg-237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "S=1.38 #energy flux in KW/m**2\n", "c=3e8 #speed of light in m/sec\n", "mu_0=4*math.pi*1e-7 #permeability of free space in H/m\n", "E0=math.sqrt(2*mu_0*c*S*1e3)\n", "B0=E0/c\n", "print\"Peak value of electric field is \",round(E0*1e-3,2),\"KV/m\"\n", "print\"Peak value of magnetic field is \",round(B0,7),\"Wb/m**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Peak value of electric field is 1.02 KV/m\n", "Peak value of magnetic field is 3.4e-06 Wb/m**2\n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg18:pg-237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "E0=100 #in Newton/coul.\n", "A=1e-3 #area in m**2\n", "l=100 #length in cm\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "V=A*l*1e-2\n", "U=e0*E0**2*V/2\n", "print\"Energy contained in cylinder is \",U,\"Joule\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Energy contained in cylinder is 4.425e-11 Joule\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg19:pg-238" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "E0=0.05 #amplitude of electric field strength in V/m\n", "v=6 #frequency in MHz\n", "c=3e8 #speed of light in m/sec\n", "mu_0=4*math.pi*1e-7 #permeability of free space in H/m\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "T=round(1/(v*1e6),9)\n", "lamda=c/(v*1e6)\n", "H0=E0/math.sqrt(mu_0/e0)\n", "Sx_av=E0*round(H0,6)/2\n", "print\"E=\",E0,\"*sin(\",\"{:.2e}\".format(2*math.pi/T),\"t -\",(2*round(math.pi,2)/lamda),\"x) V/m\"\n", "print\"H=\",\"{:.2e}\".format(H0),\"*sin(\",\"{:.2e}\".format(2*math.pi/T),\"t -\",(2*round(math.pi,2)/lamda),\"x) A/m\" \n", "print\"B=\",round(E0/c,12),\"*sin(\",\"{:.2e}\".format(2*math.pi/T),\"t -\",(2*round(math.pi,2)/lamda),\"x) Wb/m**2\" \n", "print\"Average poynting vector S=\",Sx_av,\"Wb/m**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "E= 0.05 *sin( 3.76e+07 t - 0.1256 x) V/m\n", "H= 1.33e-04 *sin( 3.76e+07 t - 0.1256 x) A/m\n", "B= 1.67e-10 *sin( 3.76e+07 t - 0.1256 x) Wb/m**2\n", "Average poynting vector S= 3.325e-06 Wb/m**2\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg20:pg-239" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "lamda=7 #wavelength in mm\n", "E0=42 #maximum magnitude of electric field in V/m\n", "c=3e8 #speed of light in m/sec\n", "print\"E=\",E0,\"*sin(2*pi*(ct-x)/\",lamda,\") V/m\"\n", "print\"B=\",E0/c,\"*sin(2*pi*(ct-x)/\",lamda,\") Wb/m**2 \\nThe magnetic field is along Z-axis.\"\n", "#unit is not mentioned in answer in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "E= 42 *sin(2*pi*(ct-x)/ 7 ) V/m\n", "B= 1.4e-07 *sin(2*pi*(ct-x)/ 7 ) Wb/m**2 \n", "The magnetic field is along Z-axis.\n" ] } ], "prompt_number": 15 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg21:pg-239" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "er=81 #relative permittivity of distilled water\n", "e0=1 #let, permittivity of free space\n", "mu_0=1 #let, permeability of free space\n", "e=e0*er\n", "c=3e8 #speed of light in m/sec\n", "mu=mu_0#for distilled water\n", "MU=math.sqrt((mu*e)/(mu_0*e0))\n", "v=c/MU\n", "print\"Refractive index is \",MU\n", "print\"Velocity of light in distilled water is \",\"{:.2e}\".format(v),\"m/s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Refractive index is 9.0\n", "Velocity of light in distilled water is 3.33e+07 m/s\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg23:pg-241" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "E0=7.5 #electric field intensity in KV/m\n", "w=2e9 #angular frequency in rad/sec\n", "c=3e8 #speed of light in m/sec\n", "mu_0=4*round(math.pi,2)*1e-7 #permeability of free space in H/m\n", "e0=8.85e-12 #permittivity of free space in F/m\n", "f=w/(2*round(math.pi,2))\n", "lamda=c/f\n", "T=1/f\n", "H0=E0*1e3/math.sqrt(mu_0/e0)\n", "print\"Wavelength is \",lamda,\"m\"\n", "print\"Frequency is \",round(f*1e-6,1),\"MHz\"\n", "print\"Time period is \",T,\"sec\"\n", "print\"Amplitude of magnetic field intensity is \",round(H0,2),\"A/m\"\n", "print\"Therefore, Hz=\",round(H0,2),\"*cos( (%.e*t)-(beta*x)) A/m\"%w#unit is not printed in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Wavelength is 0.942 m\n", "Frequency is 318.5 MHz\n", "Time period is 3.14e-09 sec\n", "Amplitude of magnetic field intensity is 19.91 A/m\n", "Therefore, Hz= 19.91 *cos( (2e+09*t)-(beta*x)) A/m\n" ] } ], "prompt_number": 18 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg24:pg-241" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "mu_0=4*math.pi*1e-7 #permeability of free space in H/m\n", "e0=8.854e-12 #permittivity of free space in F/m\n", "#E=45*sin(6e8*pi*t-(2*pi*x))j+15*cos(6e8*pi*t-(2*pi*x))k volt/m (given equation) \n", "#E=Ey*sin((w*t)-(beta*x))j + Ez*cos((w*t)-(beta*x))k (standard form)\n", "#compairing given equation with above equation\n", "pi=1 #let\n", "beta=2*pi\n", "w=6e8*pi\n", "f=w/(2*pi)\n", "n0=math.sqrt(mu_0/e0)\n", "print\"Phase constant is %d*pi rad/s\"%beta\n", "print\"Angular frequency is %.e*pi rad/s\"%w\n", "print\"Frequency is %.e Hz\"%f\n", "print\"Intrinsic impedance is %d Ohm\"%round(n0)\n", "print\"Magnetic field is [0 %s*cos(6*pi*10**8*t-(2*pi*x)) %s*sin(6*pi*10**8*t-(2*pi*x))] A/m\"%(round(15/n0,4),round(45/n0,3)) #unit is not printed in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Phase constant is 2*pi rad/s\n", "Angular frequency is 6e+08*pi rad/s\n", "Frequency is 3e+08 Hz\n", "Intrinsic impedance is 377 Ohm\n", "Magnetic field is [0 0.0398*cos(6*pi*10**8*t-(2*pi*x)) 0.119*sin(6*pi*10**8*t-(2*pi*x))] A/m\n" ] } ], "prompt_number": 19 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg25:pg-242" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from sympy import symbols,diff,cos,sin\n", "import math\n", "x,y,B,Y=symbols('x y B Y')\n", "Hz=(6*x*cos(B))+(12*y*sin(Y))\n", "a=diff(Hz,y)\n", "b=diff(-Hz,x)\n", "c=0\n", "d=array([a,b,c])\n", "print\"J =\", d" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "J = [12*sin(Y) -6*cos(B) 0]\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg26:pg-244" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "A=1.3 #area in m**2\n", "t=3 #time in hours\n", "S=1.1 #intensity of sun rays in KW/m**2\n", "c=3e8 #speed of light in m/sec\n", "p=A*(t*3600)*(S*1000)/c\n", "print\"Momentum is %se-4 Kg-m/s\"%(p*10000)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Momentum is 514.8e-4 Kg-m/s\n" ] } ], "prompt_number": 25 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg27:pg-245" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "S=10 #energy flux in watt/m**2\n", "A=1 #area in m**2\n", "t=1 #time in hour\n", "c=3e8 #speed of light in m/sec\n", "p=2*S*A*(t*3600)/c\n", "F=2*S*A/c\n", "print\"Momentum is %.1e Kg-m/s\"%p\n", "print\"Force is %.2e N\"%F" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Momentum is 2.4e-04 Kg-m/s\n", "Force is 6.67e-08 N\n" ] } ], "prompt_number": 26 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg29:pg-251" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "mu=4*math.pi*1e-7 #permeability in H/m\n", "f=71.6 #frequency in MHz\n", "sigma=3.54e7 #conductivity in siemens/m\n", "d=1/sqrt(math.pi*f*1e6*mu*sigma)\n", "print\"Depth of penetration is \",int(round(d*1e6)),\"micro meter\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Depth of penetration is 10 micro meter\n" ] } ], "prompt_number": 27 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg30:pg-251" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "f=3e6 #frequency in Hz\n", "mu_r=1 \n", "mu_0=4*round(math.pi,2)*1e-7 # in H/m\n", "sigma=38e6 # in S/m\n", "mu=mu_r*mu_0\n", "d=1/math.sqrt(round(math.pi,2)*f*mu*sigma)\n", "alpha=1/(d)\n", "beta=alpha\n", "magnitude=math.sqrt(alpha**2+beta**2)\n", "angle=math.degrees(math.atan(beta/alpha))\n", "v=2*round(math.pi,2)*f/round(beta)\n", "print\"Skin depth is \",round(d*1e3,5),\"mm\"\n", "print\"Propagation constant =[ %.4e , %s degree] m**-1\"%(magnitude,int(angle)) #in polar form\n", "print\"Wave velocity is \",round(v,2),\"m/s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Skin depth is 0.04716 mm\n", "Propagation constant =[ 2.9987e+04 , 45 degree] m**-1\n", "Wave velocity is 888.51 m/s\n" ] } ], "prompt_number": 30 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg31:pg-252" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "mu=4*math.pi*1e-7 # in H/m\n", "e0=8.854e-12 # in F/m\n", "e=70*e0\n", "sigma=5\n", "d=(2./sigma)*math.sqrt(e/mu)\n", "alpha=1/round(d,4)\n", "print\"skin depth is \",round(d,4),\"m\"\n", "print\"Attenuation constant is \",round(alpha,2),\"Np/m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "skin depth is 0.0089 m\n", "Attenuation constant is 112.36 Np/m\n" ] } ], "prompt_number": 31 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg32:pg-253" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import cmath\n", "sigma=2e-3 #in S/m\n", "e0=8.854e-12 #in F/m\n", "e=80*e0\n", "f=10 #in KHz\n", "mu=4*math.pi*1e-7 #in H/m\n", "ratio=sigma/(2*round(math.pi,2)*f*1e3*e)\n", "\n", "#since ratio= sigma/(w*e) = 44.96 >>1,therefore, medium is a good conductor.\n", "#So calculations will be done considering medium as a good conductor.\n", "\n", "alpha=math.sqrt(2*math.pi*f*1e3*mu*sigma/2)\n", "beta=int(alpha*1e5)*1e-5\n", "magnitude=math.sqrt(alpha**2+beta**2)\n", "angle=math.degrees(math.atan(beta/alpha))\n", "ni=round(round(math.sqrt(2*math.pi*f*1e3*mu/sigma),2)/round(math.sqrt(2),2),3)*(1+1j)\n", "lamda=2*round(math.pi,2)/beta\n", "v=2*math.pi*f*1e3/beta\n", "print\"Attenuation constant is %.2e neper/m\"%(int(alpha*1e5)*1e-5)\n", "print\"Phase constant is %.2e rad/m\"%beta\n", "print\"Propagation constant = [ %.3e , %.f degree] m**-1\"%(magnitude,angle)#in polar form(unit is not printed in book) \n", "print\"Intrinsic impedance is \",ni,\"ohm\"\n", "print\"Wavelength is %.2f m\"%lamda\n", "print\"Velocity of wave is %.2e m/s\"%v" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Attenuation constant is 8.88e-03 neper/m\n", "Phase constant is 8.88e-03 rad/m\n", "Propagation constant = [ 1.256e-02 , 45 degree] m**-1\n", "Intrinsic impedance is (4.454+4.454j) ohm\n", "Wavelength is 707.21 m\n", "Velocity of wave is 7.08e+06 m/s\n" ] } ], "prompt_number": 33 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg33:pg-254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "f=100 #in MHz\n", "mu_r=1\n", "mu_0=4*round(math.pi,2)*1e-7 #in H/m\n", "mu=mu_0*mu_r\n", "sigma=58e6 #in S/m\n", "alpha=math.sqrt(round(math.pi,2)*f*1e6*mu*sigma)\n", "alpha=int(alpha/10)*10\n", "beta=alpha\n", "magnitude=math.sqrt(alpha**2+beta**2)\n", "angle=math.degrees(math.atan(beta/alpha))\n", "sqrt_j=45\n", "ni=sqrt(2*round(math.pi,2)*f*1e6*mu/sigma)\n", "v=2*round(math.pi,2)*f*1e6/beta\n", "print\"Attenuation constant is %.4e neper/m\"%(int(alpha*1e5)*1e-5)\n", "print\"Phase constant is %.4e rad/m\"%beta\n", "print\"Propagation constant = [ %.4e , %.f degree] m**-1\"%(magnitude,angle)#in polar form(unit is not printed in book) \n", "print\"Intrinsic impedance = [ %.3e , %s degree ] ohm\"%(ni,sqrt_j)#in polar form(unit is not printed in book)\n", "print\"Velocity of wave is %.3f Km/s\"%(v/1e3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Attenuation constant is 1.5124e+05 neper/m\n", "Phase constant is 1.5124e+05 rad/m\n", "Propagation constant = [ 2.1389e+05 , 45 degree] m**-1\n", "Intrinsic impedance = [ 3.688e-03 , 45 degree ] ohm\n", "Velocity of wave is 4.152 Km/s\n" ] } ], "prompt_number": 34 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg34:pg-255" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "mu=4*math.pi*1e-7 #in H/m\n", "sigma=3.54e7 #in S/m\n", "d=0.0664 #penetration depth in mm\n", "f=1/(math.pi*mu*sigma*(d*1e-3)**2)\n", "print\"Frequency is %.2f MHz\"%(f/1e6)\n", "#answer is wrong in book because d=0.0644 is taken in calculation which is wrong(given d=0.0664 mm)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Frequency is 1.62 MHz\n" ] } ], "prompt_number": 36 } ], "metadata": {} } ] }