AC Fundamentals Objectives Part 07
120 The frequency of the current will be 60 Hz.
121 The phase angle between the current and the voltage will be 𝟎°.
122 The dc applied voltage necessary for the same heating affect in the resistance will be
120 V.
Questions 123 to 124 refer to data given below:
An a.c wave form with a frequency of 1.5 kHz has a peak value of 3.3 V.
123 The instantaneous value of voltage at 0.65 micro-second will be 20.2 mV
124 The instantaneous value at 1.2 milli-seconds will be –3.1 V.
Questions 125 to 128 refer to data given below:
The circuit shown in figure below has a 60 Hz supply voltage with a maximum value
of 160 V.
125 The instantaneous current at 𝜋⁄4 radians will be 11.3 A.
126 The instantaneous power at 𝜋⁄4 radians will be 2.56 kW.
127 The instantaneous value of current at5𝜋4radians will be –5.5 A.
128 The instantaneous power at3𝜋4radians will be 2.56 kW.
Questions 129 to 132 refer to data given below:
A 300 V sinusoidal ac supply is applied to a 50-ohm resistor.
129 The peak value of current through the resistor will be 8.28 A.
30 The rms value of current through the resistor will be 6 A.
131 The average value of current for the half cycle will be 5.4 A.
132 The power dissipated in the resistor will be 1.8 kW.
Questions 133 to 135 refer to data given below:
A conducting loop rotated in the magnetic field has an axial length of 𝑙 = 30𝑐𝑚 and a
distance between sides of 𝐷 = 8𝑐𝑚. The flux density of the magnetic field is 𝐵 = 0.25
Tesla and the loop is rotated at 140 revolutions per minute.
133 The output voltage will be 28 mV.
134 If the loops has10 turns instead of one the maximum output voltage will be 880 mV.
135 For the generator with 10 turns the instantaneous level of voltage at5𝜋4radians from
𝑒 = 0 will be –0.62 V.
136 In the above case the value of output voltage at 25 ms from 𝑒 = 0 will be 315.4 mV.
Questions 137 to 139 refer to data given below:
A sisusoidal waveform with an rms value of 6 V and a frequency of 30 Hz is applied across a 120Ω resistor.
137 The instantaneous power dissipated in the resistor at 5.5 milli-seconds from the time that the waveform commences to grow positively from zero, will be 0.44 W.
138 The peak instantaneous power dissipated in the resistor will be 6 W.
139 The average power dissipated in the resistor will be 0.3 W.
40 90<33.7°×25.5<11.3°=𝟐𝟐𝟗𝟓<−22.4°.
