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{
"metadata": {
"name": "Chapter2",
"signature": "sha256:ac80f9dfe1725f11a5d4ce0fbda5ffed825d99c680f116629e5e3fcb8b69c198"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": "2: Lasers"
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example number 2.1, Page number 52"
},
{
"cell_type": "code",
"collapsed": false,
"input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590; #wavelength(nm)\nh = 6.625*10**-34; #planck's constant\nc = 3*10**8; #velocity of light(m/s)\nk = 1.38*10**-23; #boltzmann's constant\nT = 523; #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9; #wavelength(m) \n#n1byn2 = math.exp(-(E2-E1)/(k*T))\n#but E2-E1 = h*new and new = c/lamda\n#therefore n1byn2 = math.exp(-h*c/(lamda*k*T))\nn1byn2 = math.exp(-h*c/(lamda*k*T));\n\n#Result\nprint \"relative population of Na atoms is\",n1byn2",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "relative population of Na atoms is 5.36748316686e-21\n"
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example number 2.2, Page number 53"
},
{
"cell_type": "code",
"collapsed": false,
"input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 590; #wavelength(nm)\nh = 6.625*10**-34; #planck's constant\nc = 3*10**8; #velocity of light(m/s)\nk = 1.38*10**-23; #boltzmann's constant\nT = 523; #temperature(Kelvin)\n\n#Calculation\nlamda = lamda*10**-9; #wavelength(m) \n#n21dashbyn21 = 1/(math.exp(h*new/(k*T))-1)\n#but new = c/lamda\n#therefore n21dashbyn21 = 1/(math.exp(h*c/(lamda*k*T))-1)\nA = math.exp(h*c/(lamda*k*T))-1;\nn21dashbyn21 = 1/A; \n\n#Result\nprint \"ratio of stimulated to spontaneous emission is\",n21dashbyn21\nprint \"answer given in the book is wrong\"",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "ratio of stimulated to spontaneous emission is 5.36748316686e-21\nanswer given in the book is wrong\n"
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example number 2.3, Page number 53"
},
{
"cell_type": "code",
"collapsed": false,
"input": "#importing modules\nimport math\n\n#Variable declaration\nlamda = 632.8; #wavelength of laser(nm)\nh = 6.625*10**-34; #planck's constant\nc = 3*10**8; #velocity of light(m/s)\np = 3.147; #output power(mW)\n\n#Calculation\np = p*10**-3; #output power(W)\nlamda = lamda*10**-9; #wavelength(m) \nnew = c/lamda; #frequency(Hz)\nE = h*new; #energy of each photon(J)\nEm = p*60; #energy emitted per minute(J/min)\nN = Em/E; #number of photons emitted per second\n\n#Result\nprint \"number of photons emitted per second is\",N",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "number of photons emitted per second is 6.01183879245e+17\n"
}
],
"prompt_number": 3
}
],
"metadata": {}
}
]
}
|
