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{
"metadata": {
"name": "",
"signature": "sha256:e20abe68023c39c2fa0cfc7eae20109c8c692466fb3387d83d01339972209a5e"
},
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"20: Magnetic materials"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 20.1, Page number 39"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"M=2300; #magnetisation(A/m)\n",
"B=0.00314; #flux density(Wb/m**2)\n",
"mew0=4*math.pi*10**-7;\n",
"\n",
"#Calculation\n",
"H=(B/mew0)-M; #magnetizing force(A/m)\n",
"mew_r=(M/H)+1; #relative permeability\n",
"\n",
"#Result\n",
"print \"magnetizing force is\",round(H,4),\"A/m\"\n",
"print \"relative permeability is\",round(mew_r,5)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"magnetizing force is 198.7326 A/m\n",
"relative permeability is 12.57334\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 20.2, Page number 40"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"H=10**4; #magnetic field intensity(A/m)\n",
"chi=3.7*10**-3; #susceptibility\n",
"mew0=4*math.pi*10**-7;\n",
"\n",
"#Calculation\n",
"M=chi*H; #magnetisation(A/m)\n",
"B=mew0*(M+H); #flux density(Wb/m**2)\n",
"\n",
"#Result\n",
"print \"magnetisation is\",M,\"A/m\"\n",
"print \"flux density is\",round(B*10**2,2),\"*10**-2 Wb/m**2\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"magnetisation is 37.0 A/m\n",
"flux density is 1.26 *10**-2 Wb/m**2\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 20.3, Page number 41"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"a=2.5*10**-10; #interatomic spacing(m)\n",
"M=1.8*10**6; #magnetisation(A/m)\n",
"n=2; #number of atoms present in unit cell\n",
"e=1.6*10**-19; #charge of electron(c)\n",
"m=9.1*10**-31; #mass of electron(kg)\n",
"h=6.625*10**-34; #planck's constant\n",
"\n",
"#Calculation\n",
"nv=n/(a**3); #number of atoms present per unit volume(per m**3)\n",
"Ma=M/nv; #magnetisation produced per atom(A/m**2)\n",
"beta=e*h/(4*math.pi*m); #bohr magneton(A/m**2)\n",
"Ma=Ma/beta; #magnetisation produced per atom(bohr magneton)\n",
"\n",
"#Result\n",
"print \"average magnetisation produced per atom is\",round(Ma,3),\"bohr magneton\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"average magnetisation produced per atom is 1.517 bohr magneton\n"
]
}
],
"prompt_number": 7
}
],
"metadata": {}
}
]
}
|
