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{
"metadata": {
"name": "Chapter16",
"signature": "sha256:8da1ca227cbd2fcd5141a76f92c8c3cee05db901d462b1e82e4eb0345baf65a5"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 16:Cosmology: Origin and Fate of Universe"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16.1 Page 529"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#initiation of variable\n",
"from math import log\n",
"N2=0.25;N1=0.75; #various given values\n",
"L2=1.0;L1=0.0;\n",
"E1_E2=-4.7*(10**-4); #Energy difference\n",
"\n",
"#calculation\n",
"a=(N2/N1); b=(((2*L2)+1)/((2*L1)+1));c=E1_E2; #various terms involved in the formula of ratio of population\n",
"kT=(c/log(a/b)); #value of k*T\n",
"k=0.0000856; #constant\n",
"T=kT/k; #temperature of interstellar space\n",
"\n",
"#result\n",
"print \"The temperature of interstellar space was found out to be in K\",round(T,3);"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The temperature of interstellar space was found out to be in K 2.499\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16.2 Page 536"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#initiation of variable\n",
"mc2=940.0*10**6; k=8.6*10**-5; #various constants and given values in suitable units\n",
"\n",
"#calculation\n",
"T= mc2/k; #temperature of the photons\n",
"\n",
"#result\n",
"print \"The temperature of the photons must be in K %.1e\" %round(T,3);\n",
"\n",
"#part2\n",
"t=((1.5*10**10)/T)**2; #age of universe when the photons have the above temperature\n",
"\n",
"#result\n",
"print\"The age of the universe for the temperature of the photon to be as obtained above in seconds is %.0e\" %t;"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The temperature of the photons must be in K 1.1e+13\n",
"The age of the universe for the temperature of the photon to be as obtained above in seconds is 2e-06\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16.3 Page 539"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#initiation of variable\n",
"from math import exp\n",
"k=8.62*10**-5; #various values and constants\n",
"T= 1.5*10**10;\n",
"delE=1.3*10**6;\n",
"\n",
"#calculation\n",
"a= delE/(k*T); #exponent in boltzmann factor\n",
"b=exp(-a); #ratio of neutron to protons\n",
"r=(1/(1+b))*100; #relative number of protons\n",
"\n",
"#result\n",
"print\"The percentage of protons is\",round(r),\" neutrons is \",round(100-r);"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The percentage of protons is 73.0 neutrons is 27.0\n"
]
}
],
"prompt_number": 6
}
],
"metadata": {}
}
]
}
|
