{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 3:Magnetic Properties of Materials" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.1,Page No:3.2" ] }, { "cell_type": "code", "execution_count": 51, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Magnetic moment = 9.319e-24 Am**2\n", "Bohr magneton = 9.28e-24 J/T\n" ] } ], "source": [ "import math\n", "\n", "# Variable declaration\n", "r = 0.53*10**-10; # orbit radius m\n", "n = 6.6*10**15; # frequency of revolution of electronHz\n", "e = 1.6*10**-19 # charge of electron in coulombs\n", "h = 6.63*10**-34; # plancks constant in J.s\n", "m = 9.1*10**-31; # mass of electron in kg\n", "\n", "# Calculations\n", "i = e*n # current produced due to electron\n", "A = math.pi*r*r # Area in m^2\n", "u = i*A; # magnetic moment A*m^2\n", "ub = (e*h)/float(4*math.pi*m); # Bohr magneton in J/T\n", "\n", "#result\n", "print'Magnetic moment = %3.3e'%u,'Am**2';\n", "print'Bohr magneton = %3.2e'%ub,'J/T';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.2,Page No:3.4" ] }, { "cell_type": "code", "execution_count": 52, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Magnetic moment = 2.87e+02 A-m**2\n", "\n", " Note: Instead of 2.87*10**2, 2.87*10**-2 is printed in textbook\n" ] } ], "source": [ "import math\n", "\n", "#Variable declaration\n", "ur = 1150; # relative permeability\n", "n = 500; # turns per m\n", "V = 10**-3; # volume of iron rod in m**3\n", "i = 0.5; # current in amp\n", "\n", "#Calculations\n", "#B = uo(H+M)\n", "# B = uH, u/uo = ur\n", "# M = (ur - 1)H\n", "#if current is flowing through a solenoid having n turns/l then H = ni\n", "\n", "M = (ur - 1)*n*i # magnetisation\n", "m = M*V; # magnetic moment\n", " \n", "#Output\n", "print'Magnetic moment = %3.2e'%m,' A-m**2';\n", "print'\\n Note: Instead of 2.87*10**2, 2.87*10**-2 is printed in textbook';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.3,Page No:3.5" ] }, { "cell_type": "code", "execution_count": 53, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Magnetic Moment of the rod = 2.1 A-m**2\n", "Note: In textbook length of iron rod given as 2m whereas in calculation it is wrongly taken as 0.2m\n" ] } ], "source": [ "import math\n", "\n", "# Variable declaration\n", "ur = 90; #relative permeability\n", "n = 300; # turns per m\n", "i = 0.5; # current in amp\n", "d = 10*10**-3; # diameter of iron rod\n", "l = 2; # length of iron rod\n", "\n", "#Calculations\n", "V = math.pi*(d/float(2))**2 * l; #volume of rod\n", "M = (ur - 1)*n*i; # magnetisation\n", "m = M*V; # magnetic moment\n", "\n", "# Output\n", "print'Magnetic Moment of the rod = %3.3g'%m,'A-m**2';\n", "print'Note: In textbook length of iron rod given as 2m whereas in calculation it is wrongly taken as 0.2m';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.4,Page No:3.5" ] }, { "cell_type": "code", "execution_count": 54, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Change in magnetic moment = 3.9e-29 J/T\n" ] } ], "source": [ "import math\n", "\n", "#Variable declaration\n", "Bo = 2; # magnetic field in tesla\n", "r = 5.29*10**-11 # radius in m\n", "m = 9.1*10**-31; # mass of electron in kg\n", "e = 1.6*10**-19 # charge of electron\n", "\n", "# calculations\n", "du = (e**2 * Bo * r**2)/float(4*m); # change in magnetic moment(indicating oth in -ve and +ve values)\n", "\n", "#result\n", "print'Change in magnetic moment = %3.1e'%du,'J/T';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.6,Page No:3.6" ] }, { "cell_type": "code", "execution_count": 55, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Temperature to which substance to be cooled = 7.7 K\n", "Note:Values given in question B = 52, u = 924*10**-24.Values substituted in calculation B = 5.2, u = 9.24*10**-24\n" ] } ], "source": [ "import math\n", "\n", "# Variable declaration\n", "u1 = 3.3; # magnetic dipole moment\n", "u = 9.24*10**-24;\n", "B = 5.2; # magnetic field in tesla\n", "k = 1.38*10**-23; # boltzmann constant\n", "\n", "# calculations\n", "T = (u*u1*B)/float(1.5*k); # Temperature in Kelvin\n", "\n", "#result\n", "print'Temperature to which substance to be cooled = %3.1f'%T,'K';\n", "print'Note:Values given in question B = 52, u = 924*10**-24.Values substituted in calculation B = 5.2, u = 9.24*10**-24';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.7,Page No:3.7" ] }, { "cell_type": "code", "execution_count": 56, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Magnetisation = -0.48 A/m\n", "flux density = 0.14 Tesla\n", "relative permeability = 0.999996\n" ] } ], "source": [ "import math\n", "\n", "#Variable declaration\n", "xm = -4.2*10**-6; # magnetic susceptibility in A.m**-1\n", "H = 1.15*10**5; # magnetic field in A.m**-1\n", "\n", "#Calculations\n", "uo = 4*math.pi*10**-7; # magnetic permeability N·A**-2\n", "M = xm*H; # magnetisation in A.m**-1\n", "B = uo*(H + M); # flux density in T\n", "ur = 1+(M/float(H)); # relative permeability \n", "\n", "# result\n", "print'Magnetisation = %3.2f'%M,'A/m';\n", "print'flux density = %3.2f'%B,'Tesla'; \n", "print'relative permeability = %f'%ur;\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.8,Page No:3.8" ] }, { "cell_type": "code", "execution_count": 57, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Percentage increase = 0.0014 %\n" ] } ], "source": [ "import math\n", "\n", "# Variable declaration\n", "xm = 1.4*10**-5; # magnetic susceptibility\n", "# B = uoH\n", "# B' = uruoH\n", "# ur = 1+xm\n", "# from above equations\n", "#B' = (1+xm)B\n", "# percentage increase in magnetic induction = ((B'-B)/B)*100\n", "# y = (((1+xm)B - B)/B)*100\n", "PI = xm*100; # percentage increase\n", "\n", "# Output\n", "print'Percentage increase = %3.4f'%PI,'%';\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.9,Page No:3.8" ] }, { "cell_type": "code", "execution_count": 58, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "magnetisation = -0.02 A/m\n", "Magnetic flux density = 0.0126 T\n" ] } ], "source": [ "import math\n", "\n", "# Variable declaration\n", "xm = -0.2*10**-5; # magnetic susceptability in A.m**-1\n", "H = 10**4; # magnetic field in A/m\n", "\n", "\n", "# Calculations\n", "uo = 4*math.pi*10**-7; # magnetic permeability\n", "M = xm*H # magnetisation in A/m\n", "B = uo*(H+M); # magnetic flux density in T\n", "\n", "# Output\n", "print'magnetisation = %3.2f'%M,'A/m';\n", "print'Magnetic flux density = %3.4f'%B,'T';\n" ] }, { "cell_type": "markdown", "metadata": { "collapsed": true }, "source": [ "# Example 3.10,Page No:3.8" ] }, { "cell_type": "code", "execution_count": 59, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "permeability =1.000021\n", "relative permeability =1.2567e-06 N/A**2\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "sighem = 2.1*10**-5; #magnetic susceptability\n", "u1 = 10**-7;\n", "\n", "#calculation\n", "u0 = 4*math.pi*u1;\n", "ur = 1+(sighem); #permeability\n", "u = u0*ur; #relative permeability in N/A**2\n", "\n", "#result\n", "print'permeability =%3.6f'%ur;\n", "print'relative permeability =%3.4e'%u,'N/A**2';\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.11,Page No:3.9" ] }, { "cell_type": "code", "execution_count": 60, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "permeability =1.084000\n", "relative permeability =1.362e-06 N/A**2\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "sighem = 0.084; #magnetic susceptability\n", "u1 = 10**-7;\n", "\n", "\n", "#calculation\n", "u0 = 4*math.pi*u1;\n", "ur = 1+(sighem); #permeability\n", "u = u0*ur; #relative permeability in N/A**2\n", "\n", "#result\n", "print'permeability =%3.6f'%ur;\n", "print'relative permeability =%3.3e'%u,'N/A**2';" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.12,Page No:3.9" ] }, { "cell_type": "code", "execution_count": 61, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "relative permiability =1.00267e+05\n", " Note:Calculation mistake in textbook in calculating sighe by taking ur as 10**5 instead of 100318.4\n" ] } ], "source": [ "import math\n", "\n", "#variable declarationn\n", "u = 0.126; #permiability in N/A**2\n", "u1 = 10**-7;\n", "\n", "\n", "#calculation\n", "u0 = 4*math.pi*u1;\n", "ur = u/float(u0);\n", "sighe = ur-1; #magnetic susceptability\n", "\n", "#result\n", "print'relative permiability =%3.5e'%sighe;\n", "print' Note:Calculation mistake in textbook in calculating sighe by taking ur as 10**5 instead of 100318.4';" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#Example 3.13,Page No:3.16" ] }, { "cell_type": "code", "execution_count": 62, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "susceptability of diamagnetic material = -1.1878e-07\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "#diamagnetic susceptability of He\n", "R = 0.6*10**-10; #mean radius of atom in m\n", "N = 28*10**26; #avagadro number in per m**3\n", "e = 1.6*10**-19; #charge of electron in coulombs\n", "m = 9.1*10**-31; #mass of electron in kilograms\n", "Z = 2; #atomic number\n", " \n", "#calculation\n", "u0 = 4*math.pi*10**-7; #atomic number\n", "si = -(u0*Z*(e**2)*N*(R**2))/float(6*m); #susceptability of diamagnetic material \n", " \n", "#result\n", "print'susceptability of diamagnetic material = %3.4e'%si;\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#Example 3.14,Page No:3.17" ] }, { "cell_type": "code", "execution_count": 63, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "permiability =5.00e-04 N/A**2\n", "susceptability =396.887358\n", "Note:answer of permiability is wrong in textbook\n", "Note: calcuation mistake in textbook in sighem\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "phi = 2*10**-5; #magnetic flux in Wb/m**2\n", "H = 2*10**3; #in A/m\n", "A = 0.2*10**-4; #area in m**2\n", "\n", " \n", " \n", "#calculation\n", "u0 = 4*math.pi*10**-7;\n", "B = phi/float(A); #magnetic flux density in Wb/m**2\n", "u = B/float(H); #permiability in A**-2\n", "sighem = (u/float(u0))-1;\n", " \n", "#result\n", "print'permiability =%3.2e'%u,'N/A**2';\n", "print'susceptability =%4f'%sighem;\n", "print'Note:answer of permiability is wrong in textbook';\n", "print'Note: calcuation mistake in textbook in sighem';\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.15,Page No:3.17" ] }, { "cell_type": "code", "execution_count": 64, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "susceptability of diamagnetic material = 5.61e-07\n" ] } ], "source": [ "# import math\n", "\n", "#variable declaration\n", "N = 6.5*10**25; #number of atoms in atoms per m**3\n", "e = 1.6*10**-19; #charge of electron in coulombs\n", "m = 9.1*10**-31; #mass of electron inilograms\n", "h = 6.6*10**-34; #planck's constant in J.s\n", "T = 300; #temperature in K\n", "k = 1.38*10**-23; #boltzman constant in J*(K**-1)\n", "n = 1; #constant\n", " \n", " \n", "#calculation\n", "u0 = 4*math.pi*10**-7;\n", "M = n*((e*h)/float(4*math.pi*m)); #magnetic moment in A*m**2\n", "sighe = (u0*N*(M**2))/float(3*k*T); #susceptability of diamagnetic material\n", " \n", "#result\n", "print'susceptability of diamagnetic material = %3.2e'%sighe;" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.16,Page No:3.20" ] }, { "cell_type": "code", "execution_count": 65, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "ampere turn =200 A/m\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "L = 2.0; #length in m\n", "A = 4*10**-4; #cross section sq.m\n", "u = 50*10**-4; #permiability in H*m**-1\n", "phi = 4*10**-4; #magnetic flux in Wb\n", "\n", "#calculation\n", "B = phi/float(A); #magnetic flux density in Wb/m**2\n", "NI = B/float(u); #ampere turn in A/m\n", " \n", "#result\n", "print'ampere turn =%3.0f'%NI,'A/m';\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.17,Page No:3.20" ] }, { "cell_type": "code", "execution_count": 66, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "current =1 A\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "H = 5*10**3; #corecivity in A/m\n", "l = 10**-1; #length in m\n", "n = 500; #number of turns\n", "\n", "#calculation\n", "N = n/float(l); #number of turns per m\n", "i = H/float(N); #current in A\n", " \n", "#result\n", "print'current =%1d'%i,'A';\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.18,Page No:3.20" ] }, { "cell_type": "code", "execution_count": 67, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "number of turns =5.128205\n", " Note: calculation mistake in textbook in calculattig H by taking B value as 0.06 instead of 0.0666\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "A = 6*10**-4; #area in m**2\n", "l = 0.5; #length in m\n", "u = 65*10**-4; #permiability in H/m\n", "phi = 4*10**-5; #magnetic flux in Wb\n", "\n", "\n", "#calculation\n", "B = phi/float(A);\n", "H = B/float(u);\n", "N = H*l; #number of turns\n", " \n", "#result\n", "print'number of turns =%1f'%N;\n", "print' Note: calculation mistake in textbook in calculattig H by taking B value as 0.06 instead of 0.0666';\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.19,Page No:3.21" ] }, { "cell_type": "code", "execution_count": 68, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "susceptability =1908\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "A = 0.2*10**-4; #area in m**2\n", "H = 500; #magnetising field in A.m**-1\n", "phi = 2.4*10**-5; # magnetic flux in Wb\n", "\n", "#calculation\n", "u0 = 4*math.pi*10**-7;\n", "B = phi/float(A); #magnetic flux density in N*A**-1 *m**-1\n", "u = B/float(H); #permiability in N/m\n", "fm = (u/float(u0))-1; #susceptability \n", " \n", "#result\n", "print'susceptability =%3.2d'%fm;\n", "\n", " " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 3.20,Page No:3.34" ] }, { "cell_type": "code", "execution_count": 69, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "loss of energy per hour =4800.00\n", "calculation mistake in textbook in calculating Lh\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "f = 50; #number of reversals/s in Hz\n", "W = 50; #weight in kg\n", "d = 7500; #density in kg/m^3\n", "A = 200; #area in joules /m^3\n", " \n", "#calculation\n", " \n", "V = 1/float(d); #volume of 1 kg iron\n", "E = A*V; #loss of energy per kg\n", "L = f*E; #hysteresisloss/s in Joule/second\n", "Lh = L*60*60; #loss per hour\n", " \n", "#calculation\n", "print'loss of energy per hour =%3.2f'%Lh;\n", "print'calculation mistake in textbook in calculating Lh';" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#Example 3.21,Page No:3.34" ] }, { "cell_type": "code", "execution_count": 70, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "total iron loss =2.97 watt/kg\n" ] } ], "source": [ "import math\n", "\n", "#variable declaration\n", "f = 50; #frequency in Hz\n", "Bm = 1.1; #magnetic flux in Wb/m**2\n", "t = 0.0005; #thickness of sheet \n", "p = 30*10**-8*7800; #resistivity in ohms m\n", "d = 7800; #density in kg/m**3\n", "Hl = 380; #hysteresis loss per cycle in W-S/m**2\n", "\n", "#calculation\n", "Pl = ((math.pi**2)*(f**2)*(Bm**2)*(t**2))/float(6*p); #eddy current loss\n", "Hel = (Hl*f)/float(d); #hysteresis loss\n", "Tl = Pl+Hel; #total iron loss watt/kg\n", " \n", "#result\n", "print'total iron loss =%3.2f'%Tl,' watt/kg';\n", " " ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [] } ], "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": "2.7.6" } }, "nbformat": 4, "nbformat_minor": 0 }