{
 "metadata": {
  "name": "MP-16"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": "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\nfrom math import log\nN2=0.25;N1=0.75;                                #various given values\nL2=1.0;L1=0.0;\nE1_E2=-4.7*(10**-4);                             #Energy difference\n\n#calculation\na=(N2/N1); b=(((2*L2)+1)/((2*L1)+1));c=E1_E2; #various terms involved in the formula of ratio of population\nkT=(c/log(a/b));                              #value of k*T\nk=0.0000856;                                 #constant\nT=kT/k;                 #temperature of interstellar space\n\n#result\nprint \"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\nmc2=940.0*10**6; k=8.6*10**-5; #various constants and given values in suitable units\n\n#calculation\nT= mc2/k;       #temperature of the photons\n\n#result\nprint \"The temperature of the photons must be in K %.1e\" %round(T,3);\n\n#part2\nt=((1.5*10**10)/T)**2;       #age of universe when the photons have the above temperature\n\n#result\nprint\"The age of the universe for the temperature of the photon to be as obtained above in seconds is %.01e\" %t;",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "The temperature of the photons must be in K 1.1e+13\nThe age of the universe for the temperature of the photon to be as obtained above in seconds is 1.883318e-06\n"
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": "Example 16.3 Page 539"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#initation of variable\nfrom math import exp\nk=8.62*10**-5; #various values and constants\nT= 1.5*10**10;\ndelE=1.3*10**6;\n\n#calculation\na= delE/(k*T);  #exponent in boltzmann factor\nb=exp(-a);        #ratio of neutron to protons\nr=(1/(1+b))*100;     #relative number of protons\n\n#result\nprint\"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": {}
  }
 ]
}