Alternating Current  MCQs

MCQs of Alternating Current

Showing 161 to 168 out of 168 Questions
161.
A current of 25πHZ frequency is passing through an A.C. circuit having series combination of R = 100 Ω and L = 2 H, the phase difference between voltage and current is _____ .
(a) 90°
(b) 30°
(c) 60°
(d) 45°
Answer:

Option (d)

162.
In A.C. circuit having only capacitor, the current _____ .
(a) lags behind the voltage by π2 in phase
(b) leads the voltage by π in phase
(c) leads the voltage by π2 in phase
(d) lags behind the voltage by π in phase
Answer:

Option (c)

163.
An alternating voltage given as V = 100 2 sin 100t volt is applied to a capacitor of 1 μF. The current reading of the ammeter will be equal to _____ mA.
(a) 10
(b) 40
(c) 20
(d) 80
Answer:

Option (a)

164.
For a step-down transformer which of the following is correct ?
(a) Output voltage > Input voltage
(b) Output voltage < Input voltage
(c) Number of turns in primary coil = number of turns in the secondary coil
(d) None of these
Answer:

Option (b)

165.
For L-C-R A.C. circuit resonance frequency is 5000 Hz and frequencies at half power points are 4950 Hz an 5050 Hz. The Q- factor is _____.
(a) 0.02
(b) 50
(c) 100
(d) 0.01
Answer:

Option (b)

166.
For an A.C. L-C-R series circuit at resonant frequency, which of the following is wrong ?
(a) Magnitude of reactance due to L and C are equal.
(b) Phase change due to L is equal and opposite to phase change due to C.
(c) Value of resistance is zero.
(d) Impedance has only real component.
Answer:

Option (c)

167.
If angular frequency of an A.C. source used in L-C-R circuit is decreased, then inductive reactance _____ and capacitive reactance _____ .
(a) Increase, increase
(b) Increase, decrease
(c) Decrease, increase
(d) Decrease, decrease
Answer:

Option (c)

168.
Current of 50π Hz frequency is passing through an A.c. circuit having series combination of resistance R = 100 Ω and inductor L= 3 H. The phase difference between the voltage and current is _____ .
(a) 45°
(b) 60°
(c) 30°
(d) 90°
Answer:

Option (b)

Showing 161 to 168 out of 168 Questions