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Free download in PDF Circuit Theory Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(1)
For a frequency of 200 Hz, the time period will be
[A]
0.005 s
[B]
0.5 s
[C]
0.0005 s
[D]
0.05 s
(2)
For a sine wave with peak value Emax______8.30. the average value is
[A]
lAUEmax
[B]
0.636 Emax
[C]
0.707 Emax
[D]
0.434 EWc
(3)
Form factor for a sine wave is
[A]
1.414
[B]
0.707
[C]
1.11
[D]
0.637
(4)
Form Factor is the ratio of
[A]
r.m.s. value/average value
[B]
r.m.s. value/peak value
[C]
average value/r.m.s. value
[D]
average value/peak value
Answer: r.m.s. value/average value
(5)
For a sine wave with peak value Imax the r.m.s. value is
[A]
0.5 Imax
[B]
0.707
[C]
0.9
[D]
1.414 Lmax
(6)
For the same peak value, which of the following wave has the least mean value ?
[A]
half wave rectified sine wave
[B]
triangular wave
[C]
sine wave
[D]
square wave
Answer: half wave rectified sine wave
(7)
For the same peak value which of the following wave will ‘have the highest r.m.s. value ?
[A]
square wave
[B]
half wave rectified sine wave
[C]
triangular wave
[D]
sine wave
(8)
The r.m.s. value and mean value is the same in the case of
[A]
triangular wave
[B]
sine wave
[C]
square wave
[D]
half wave rectified sine wave
(9)
The power consumed in a circuit element will be least when the phase difference between the current and voltage is
[A]
180″
[B]
90°
[C]
60°
[D]
none of the above
(10)
Two waves of the same frequency have opposite phase when the phase angle between them is
[A]
360°
[B]
180°
[C]
90°
[D]
0°
(11)
The voltage of domestic supply is 220V. This figure represents
[A]
mean value
[B]
r.m.s. value
[C]
peak value
[D]
average value
(12)
If two sine waves of the same frequency have a phase difference of JT radians, then
[A]
both will reach their minimum values at the same instant
[B]
both will reach their maximum values at the same instant
[C]
when one wave reaches its maxi¬mum value, the other will reach its minimum value
[D]
none of the above
Answer: when one wave reaches its maxi¬mum value, the other will reach its minimum value
(13)
The peak value of a sine wave is 200 V. Its average value is
[A]
127.4 V
[B]
141.4 V
[C]
282.8 V
[D]
200V
(14)
If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is
[A]
a sinusoid of the same frequency
[B]
a sinusoid of half the original frequency
[C]
a sinusoid of double the frequency
[D]
not a sinusoid
Answer: a sinusoid of the same frequency
(15)
A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to
[A]
average voltage
[B]
r.m.s. voltage
[C]
peak voltage
[D]
none of the above
(16)
The period of a sine wave is _____ seconds.
Its frequency is
[A]
20 Hz
[B]
30 Hz
[C]
40 Hz
[D]
50 Hz
(17)
The form factor is the ratio of
[A]
peak value to r.m.s. value
[B]
r.m.s. value to average value
[C]
average value to r.m.s. value
[D]
none of the above
Answer: r.m.s. value to average value
(18)
The period of a wave is
[A]
the same as frequency
[B]
time required to complete one cycle
[C]
expressed in amperes
[D]
none of the above
Answer: time required to complete one cycle
(19)
The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.
[A]
2.5
[B]
5
[C]
10
[D]
15
(20)
A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second.
[A]
100 n
[B]
50 jt
[C]
25 JT
[D]
5 n
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