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diff --git a/Engineering_Physics_by_Rajendran/Chapter11.ipynb b/Engineering_Physics_by_Rajendran/Chapter11.ipynb new file mode 100755 index 00000000..3f04726e --- /dev/null +++ b/Engineering_Physics_by_Rajendran/Chapter11.ipynb @@ -0,0 +1,288 @@ +{
+ "metadata": {
+ "name": "",
+ "signature": "sha256:c3dcf79a03b4887493b03eb7567c9289353e41ba9f42b1e11e4742e5d995690d"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "11: Laser"
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.1, Page number 33"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "lamda=590*10**-9; #wavelength of sodium D line(m)\n",
+ "h=6.626*10**-34; #planck's constant\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "e=1.602*10**-19; #charge of electron(eV)\n",
+ "\n",
+ "#Calculation\n",
+ "E=h*c/lamda; #energy of 1st excited state(J)\n",
+ "E=E/e; #energy of 1st excited state(eV)\n",
+ "\n",
+ "#Result\n",
+ "print \"energy of 1st excited state is\",round(E,1),\"eV\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "energy of 1st excited state is 2.1 eV\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.2, Page number 34"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "T=250+273; #temperature(K)\n",
+ "lamda=590*10**-9; #wavelength of sodium D line(m)\n",
+ "h=6.626*10**-34; #planck's constant\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "k=1.38*10**-23; #boltzmann constant\n",
+ "\n",
+ "#Calculation\n",
+ "a=h*c/(k*T*lamda);\n",
+ "N2byN1=math.exp(-a); #ratio between atoms in 1st excited state and ground state\n",
+ "\n",
+ "#Result\n",
+ "print \"ratio between atoms in 1st excited state and ground state is\",round(N2byN1*10**21,2),\"*10**-21\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "ratio between atoms in 1st excited state and ground state is 5.33 *10**-21\n"
+ ]
+ }
+ ],
+ "prompt_number": 6
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.3, Page number 34"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "T=250+273; #temperature(K)\n",
+ "lamda=590*10**-9; #wavelength of sodium D line(m)\n",
+ "h=6.626*10**-34; #planck's constant\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "k=1.38*10**-23; #boltzmann constant\n",
+ "\n",
+ "#Calculation\n",
+ "a=h*c/(k*T*lamda);\n",
+ "N2byN1=1/(math.exp(a)-1); #ratio between stimulated emission and spontaneous emission\n",
+ "\n",
+ "#Result\n",
+ "print \"ratio between stimulated emission and spontaneous emission is\",round(N2byN1*10**21,4),\"*10**-21\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "ratio between stimulated emission and spontaneous emission is 5.3298 *10**-21\n"
+ ]
+ }
+ ],
+ "prompt_number": 8
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.4, Page number 35"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "n0=1.76; #refractive index of ruby rod\n",
+ "new0=4.3*10**14; #frequency(Hz)\n",
+ "deltav0=1.5*10**11; #doppler broadening(Hz)\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "tow21=4.3*10**-3; #lifetime of spontaneous emission(s)\n",
+ "tow_photon=6*10**-9; #lifetime of photon(s)\n",
+ "\n",
+ "#Calculation\n",
+ "a=4*math.pi**2*new0**2*n0**3/(c**3);\n",
+ "N2_N1=a*tow21*deltav0/tow_photon; #difference between excited state and ground state population(per m**3)\n",
+ "\n",
+ "#Result\n",
+ "print \"difference between excited state and ground state population is\",round(N2_N1*10**-23,3),\"*10**23 per m**3\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "difference between excited state and ground state population is 1.584 *10**23 per m**3\n"
+ ]
+ }
+ ],
+ "prompt_number": 10
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.5, Page number 35"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "T=300; #temperature(K)\n",
+ "lamda=5000*10**-10; #wavelength of light(m)\n",
+ "h=6.626*10**-34; #planck's constant\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "k=1.38*10**-23; #boltzmann constant\n",
+ "\n",
+ "#Calculation\n",
+ "a=h*c/(k*T*lamda);\n",
+ "N2byN1=1/(math.exp(a)-1); #ratio between stimulated emission and spontaneous emission\n",
+ "\n",
+ "#Result\n",
+ "print \"ratio between stimulated emission and spontaneous emission is\",round(N2byN1*10**42),\"*10**-42\"\n",
+ "print \"answer varies due to rounding off errors\"\n",
+ "print \"spontaneous emission is more predominant than that of stimulated emission. for stimulating emission, N2>>N1. therefore there is no amplification possibility\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "ratio between stimulated emission and spontaneous emission is 2.0 *10**-42\n",
+ "answer varies due to rounding off errors\n",
+ "spontaneous emission is more predominant than that of stimulated emission. for stimulating emission, N2>>N1. therefore there is no amplification possibility\n"
+ ]
+ }
+ ],
+ "prompt_number": 13
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example number 11.6, Page number 36"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#importing modules\n",
+ "import math\n",
+ "from __future__ import division\n",
+ "\n",
+ "#Variable declaration\n",
+ "lamda=632.8*10**-9; #wavelength of laser beam(m)\n",
+ "h=6.626*10**-34; #planck's constant\n",
+ "c=3*10**8; #velocity of light(m/s)\n",
+ "P=2.3*10**-3; #output power(W)\n",
+ "\n",
+ "#Calculation\n",
+ "new=c/lamda; #frequency of photon(Hz)\n",
+ "E=h*new; #energy of photon(J)\n",
+ "El=P*60; #energy emitted by laser(J/min)\n",
+ "n=El/E; #number of photons emitted(photons/min)\n",
+ "\n",
+ "#Result\n",
+ "print \"number of photons emitted is\",round(n*10**-17,3),\"*10**17 photons/min\"\n",
+ "print \"answer varies due to rounding off errors\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "number of photons emitted is 4.393 *10**17 photons/min\n",
+ "answer varies due to rounding off errors\n"
+ ]
+ }
+ ],
+ "prompt_number": 22
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+}
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