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"cells": [
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"cell_type": "markdown",
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"source": [
"# Chapter 15 : Alternating voltage & current"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_1 Page No: 451"
]
},
{
"cell_type": "code",
"execution_count": 24,
"metadata": {
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"name": "stdout",
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"text": [
"The Voltage at 30° = 50.00 Volts\n",
"The Voltage at 45° = 70.71 Volts\n",
"The Voltage at 90° = 100.00 Volts\n",
"The Voltage at 270° = -100.00 Volts\n"
]
}
],
"source": [
"from numpy import sin, pi\n",
"# A sine wave of voltage varies from zero to a maximum of 100 V. How much is the voltage at the instant of 30° of the cycle? 45°? 90°? 270°?\n",
"\n",
"# Given data\n",
"\n",
"Vm = 100# # Vm=100 Volts\n",
"t1 = 30# # Theta 1=30°.\n",
"t2 = 45# # Theta 2=45°.\n",
"t3 = 90# # Theta 3=90°.\n",
"t4 = 270# # Theta 4=270°.\n",
"\n",
"v1 = Vm*sin(t1*pi/180)\n",
"print 'The Voltage at 30° = %0.2f Volts'%v1\n",
"\n",
"v2 = Vm*sin(t2*pi/180)\n",
"print 'The Voltage at 45° = %0.2f Volts'%v2\n",
"\n",
"v3 = Vm*sin(t3*pi/180)\n",
"print 'The Voltage at 90° = %0.2f Volts'%v3\n",
"\n",
"v4 = Vm*sin(t4*pi/180)\n",
"print 'The Voltage at 270° = %0.2f Volts'%v4"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_2 Page No: 456"
]
},
{
"cell_type": "code",
"execution_count": 25,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Time period = 1e-03 Seconds\n",
"i.e 1/1000 sec\n",
"The Frequency = 1000.00 Hertz\n",
"OR 1 kHz\n"
]
}
],
"source": [
"from __future__ import division\n",
"# An alternating current varies through one complete cycle in 1 ⁄ 1000 s. Calculate the period and frequency.\n",
"\n",
"# Given data\n",
"\n",
"tc = 1/1000# # One Complete Cycle=1 ⁄ 1000 sec.\n",
"\n",
"T = tc#\n",
"print 'The Time period = %0.e Seconds'%T\n",
"print 'i.e 1/1000 sec'\n",
"\n",
"f = 1/tc#\n",
"print 'The Frequency = %0.2f Hertz'%f\n",
"print 'OR 1 kHz'"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_3 Page No: 476"
]
},
{
"cell_type": "code",
"execution_count": 26,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Time period = 1e-06 Seconds of 1 MHz freq.\n",
"i.e 1*10**-6 sec = 1 usec\n",
"The Time period = 5e-07 Seconds of 2 MHz freq.\n",
"i.e 0.5*10**-6 sec = 0.5 usec\n"
]
}
],
"source": [
"# Calculate the period for the two frequencies of 1 MHz and 2 MHz.Calculate the period for the two frequencies of 1 MHz and 2 MHz.\n",
"\n",
"# Given data\n",
"\n",
"f1 = 1*10**6# # Freq=1 MHz\n",
"f2 = 2*10**6# # Freq=2 MHz\n",
"\n",
"t1 = 1/f1#\n",
"print 'The Time period = %0.e Seconds of 1 MHz freq.'%t1\n",
"print 'i.e 1*10**-6 sec = 1 usec'\n",
"\n",
"t2 = 1/f2#\n",
"print 'The Time period = %0.e Seconds of 2 MHz freq.'%t2\n",
"print 'i.e 0.5*10**-6 sec = 0.5 usec'"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_4 Page No: 478"
]
},
{
"cell_type": "code",
"execution_count": 27,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Lamda or Wavelenght = 1.00 cm\n"
]
}
],
"source": [
"# Calculate lamda for a radio wave witf f of 30 GHz.\n",
"\n",
"# Given data\n",
"\n",
"c = 3*10**10# # Speed of light=3*10**10 cm/s\n",
"f = 30*10**9# # Freq=30 GHz\n",
"\n",
"l = c/f#\n",
"print 'The Lamda or Wavelenght = %0.2f cm'%l"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_5 Page No: 480"
]
},
{
"cell_type": "code",
"execution_count": 28,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Height = 250.00 cm\n",
"The Height = 8.20 feet\n"
]
}
],
"source": [
"# The length of a TV antenna is lamda\u0005/2 for radio waves with f of 60 MHz. What is the antenna length in centimeters and feet?\n",
"\n",
"# Given data\n",
"\n",
"c = 3*10**10# # Speed of light=3*10**10 cm/s\n",
"f = 60*10**6# # Freq=60 MHz\n",
"In = 2.54# # 2.54 cm = 1 in\n",
"ft = 12# # 12 in = 1 ft\n",
"\n",
"l1 = c/f#\n",
"l = l1/2#\n",
"print 'The Height = %0.2f cm'%l\n",
"\n",
"li = l/In\n",
"lf = li/ft#\n",
"print 'The Height = %0.2f feet'%lf"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_6 Page No: 481"
]
},
{
"cell_type": "code",
"execution_count": 29,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Frequency = 50000000 Hertz\n",
"i.e 50*10**6 Hz OR 50 MHz\n"
]
}
],
"source": [
"# For the 6-m band used in amateur radio, what is the corresponding frequency?\n",
"\n",
"# Given data\n",
"\n",
"v = 3*10**10# # Speed of light=3*10**10 cm/s\n",
"l = 6*10**2# # lamda=6 meter\n",
"\n",
"f = v/l\n",
"print 'The Frequency = %0.f Hertz'%f\n",
"print 'i.e 50*10**6 Hz OR 50 MHz'"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_7 Page No: 481"
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Lamda or Wavelenght = 11.30 ft\n"
]
}
],
"source": [
"# What is the wavelength of the sound waves produced by a loudspeaker at a frequency of 100 Hz?\n",
"\n",
"# Given data\n",
"\n",
"c = 1130# # Speed of light=1130 ft/s\n",
"f = 100# # Freq=100 Hz\n",
"\n",
"l = c/f#\n",
"print 'The Lamda or Wavelenght = %0.2f ft'%l"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example No. 15_8 Page No: 482"
]
},
{
"cell_type": "code",
"execution_count": 31,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The Lamda or Wavelength = 0.03 ft\n",
"The Lamda or Wavelength = 1.00 cm\n"
]
}
],
"source": [
"# For ultrasonic waves at a frequency of 34.44 kHz, calculate the wavelength in feet and in centimeters.\n",
"\n",
"# Given data\n",
"\n",
"c = 1130# # Speed of light=1130 ft/s\n",
"f = 34.44*10**3# # Freq=100 Hz\n",
"In = 2.54# # 2.54 cm = 1 in\n",
"ft = 12# # 12 in = 1 ft\n",
"\n",
"l = c/f#\n",
"print 'The Lamda or Wavelength = %0.2f ft'%l\n",
"\n",
"a = l*ft#\n",
"\n",
"l1 = a*In#\n",
"print 'The Lamda or Wavelength = %0.2f cm'%l1"
]
}
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