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{
"metadata": {
"name": "",
"signature": "sha256:708d3f2a9798f4d28f6ce90536d50509c591ba2ba31051121346b4739b2aea82"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 8:Magnetic Properties"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.1 , Page no:236"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"X=-0.5E-5; #magnetic susceptibility of silicon\n",
"H=0.9E4; #in A/m (magnetic field intensity)\n",
"mu0=4*3.14*1E-7; #in H/m (absolute permeability)\n",
"\n",
"#calculate\n",
"I=X*H; #calculation of intensity of magnetism\n",
"B=mu0*H*(1+X); #calculation of magnetic flux density\n",
"\n",
"#result\n",
"print\"The intensity of magnetism is I=\",I,\"A/m\";\n",
"print\"The magnetic flux density is B=\",round(B,3),\"Wb/m^2\";\n",
"print \"NOTE: The answer in the textbook is wrong\" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The intensity of magnetism is I= -0.045 A/m\n",
"The magnetic flux density is B= 0.011 Wb/m^2\n",
"NOTE: The answer in the textbook is wrong\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.2 , Page no:236"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"r=0.052; #in nm (radius of orbit)\n",
"B=1; #in Wb/m^2 (magnetic field of induction)\n",
"e=1.6E-19; #in C (charge of electron)\n",
"m=9.1E-31; #in Kg (mass of electron)\n",
"\n",
"#calculate\n",
"r=0.052*1E-9; #changing unit from nm to m\n",
"d_mu=(e**2*r**2*B)/(4*m); #calculation of change in magnetic moment\n",
"\n",
"#result\n",
"print\"The change in magnetic moment is =\",'%.3E'%d_mu,\"Am^2\";\n",
"print \"NOTE: The answer in the textbook is wrong\" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The change in magnetic moment is = 1.902E-29 Am^2\n",
"NOTE: The answer in the textbook is wrong\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.3 , Page no:236"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"H=220; #in A/m (magnetic field intensity)\n",
"I=3300; #in A/m (intensity of magnetisation)\n",
"\n",
"#calculate\n",
"mu_r=1+(I/H); #calculation of relative permeability\n",
"\n",
"#result\n",
"print\"The relative permeability of a ferromagentic material is =\",mu_r;"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The relative permeability of a ferromagentic material is = 16.0\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.4 , Page no:236"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"I=3000; #in A/m (intensity of magnetisation)\n",
"B=0.005; #in Wb/m^2 (magnetic flus intensity)\n",
"pi=3.14; #value of pi used in the solution\n",
"mu0=4*pi*1E-7; #in H/m (absolute permeability)\n",
"\n",
"#calculate\n",
"H=(B/mu0)-I; #calculation of magnetic force\n",
"mu_r=(I/H)+1; #calculation of relative permeability\n",
"\n",
"#result\n",
"print\"The magnetic force is H=\",round(H,3);\n",
"print\"The relative permeability is =\",round(mu_r,3);"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The magnetic force is H= 980.892\n",
"The relative permeability is = 4.058\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.5 , Page no:237"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"H=4E3; #in A/m (magnetic field intensity)\n",
"N=60; #number of turns\n",
"l=12; #in cm (length of solenoid)\n",
"\n",
"#calculate\n",
"n=N/(l*1E-2); #calculation of number of turns per unit metre\n",
"#Snice H=n*i;\n",
"i=H/n; #calculation of current through the solenoid\n",
"\n",
"#result\n",
"print\"The current through the solenoid is i=\",i,\"A\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The current through the solenoid is i= 8.0 A\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.6 , Page no:237"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"l=30; #in cm (length of solenoid)\n",
"A=1; #in cm^2 (cross-sectional area)\n",
"N=300; #number of turns\n",
"i=0.032; #in A (current through the winding)\n",
"phi_B=2E-6; #in Wb (magnetic flux)\n",
"pi=3.14; #value of pi used in the solution\n",
"mu0=4*pi*1E-7; #in H/m (absolute permeability)\n",
"\n",
"#calculate\n",
"l=l*1E-2; #changing unit from cm to m\n",
"A=A*1E-4; #changing unit from cm^2 to m^2\n",
"B=phi_B/A; #calculation of flux density\n",
"H=N*i/l; #calculation of magnetic intensity\n",
"mu=B/H; #calcluation of absolute permeability of iron\n",
"mu_r=mu/mu0; #calcluation of relative permeability of iron\n",
"\n",
"#result\n",
"print\"The flux density is B=\",B,\"Wb/m^2\";\n",
"print\"The magnetic intensity is H=\",H,\"A-turns/m\";\n",
"print\"The relative permeability of iron is =\",round(mu_r),\" (roundoff error)\";\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The flux density is B= 0.02 Wb/m^2\n",
"The magnetic intensity is H= 32.0 A-turns/m\n",
"The relative permeability of iron is = 498.0 (roundoff error)\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.7 , Page no:238"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#given\n",
"A=100; #in m^2 (area of Hysteresis loop)\n",
"B=0.01; #in Wb/m^2 (unit space along vertical axis or magnetic flux density)\n",
"H=40; #in A/m (unit space along horizontal axis or magnetic fild ntensity)\n",
"\n",
"#calculate\n",
"H_L=A*B*H; #calculation of magnetic intensity\n",
"\n",
"#result\n",
"print\"The Hystersis loss per cycle is =\",round(H_L),\"J/m^2\";"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The Hystersis loss per cycle is = 40.0 J/m^2\n"
]
}
],
"prompt_number": 7
}
],
"metadata": {}
}
]
}
|
