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"name": "",
"signature": "sha256:141e2987b2be679ae1fc9e807cf81c12805438f836d3be09701fc88866bf9bb5"
},
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter5:LASERS"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex5.1:pg-164"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#to calculate area of the spot on the moon\n",
"lamda=6*10**-7 #wavelength in m\n",
"d=2 #diameter in m\n",
"dtheta=lamda/d #angular spread in radian\n",
"D=4*10**8 #distance of the moon\n",
"A=(D*dtheta)**2\n",
"print \"the areal spread is A=\",\"{:.2e}\".format(A),\"m**2\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the areal spread is A= 1.44e+04 m**2\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex5.2:pg-164"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#to calculate angular spread of the beam\n",
"lamda=8*10**-7 #wavelength in m\n",
"d=5*10**-3 #aperture in m\n",
"dtheta=lamda/d \n",
"print \"the angular spread of the beam is dtheta=\",\"{:.1e}\".format(dtheta),\"radian\"\n",
"#to calculate the areal spread when it reaches the moon\n",
"D=4*10**8 #distance of the moon in m\n",
"A=(D*dtheta)**2\n",
"print \"the areal spread is A=\",\"{:.3e}\".format(A),\"m**2\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the angular spread of the beam is dtheta= 1.6e-04 radian\n",
"the areal spread is A= 4.096e+09 m**2\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex5.3:pg-165"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#to calculate number of oscillations corresponding to the coherence length\n",
"L=2.945*10**-2 #coherence length in m\n",
"lamda=5890*10**-10 #wavelength of sodium light in m\n",
"n=L/lamda\n",
"print \"the number of oscillations is n=\",\"{:.1e}\".format(n),\"unitless\"\n",
"#to calculate coherence time\n",
"c=3*10**8 #light speed in m\n",
"Time=L/c #coherence time\n",
"print \"the coherence Time=\",\"{:.2e}\".format(Time),\"s\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the number of oscillations is n= 5.0e+04 unitless\n",
"the coherence Time= 9.82e-11 s\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex5.4:pg-165"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#to calculate area and intensity of the image\n",
"lamda=7200*10**-10 #wavelength in m\n",
"d=5*10**-3 #aperture in m\n",
"dtheta=lamda/d #angular spread in radian \n",
"f=0.1 #focal length in m\n",
"arealspread=(dtheta*f)**2\n",
"print \"areal spread =\",\"{:.3e}\".format(arealspread),\"m**2\"\n",
"power=50*10**-3\n",
"I=power/arealspread\n",
"print \"intensity of the image is I=\",\"{:.3e}\".format(I),\"watts/m**2\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"areal spread = 2.074e-10 m**2\n",
"intensity of the image is I= 2.411e+08 watts/m**2\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
