A.C Fundamentals, Circuits and Circuit Theory MCQs

Question 1

In a pure inductive circuit

Accepted Answer

The current lags behind the voltage by 90°

Answer

The current is in phase with the voltage

Answer

The current leads the voltage by 90°

Answer

The current can lead or lag by 90°

Question 2

In a pure resistive circuit

Accepted Answer

Current is in phase with the voltage

Answer

Current lags behind the voltage by 90°

Answer

Current leads the voltage by 90°

Answer

Current can lead or lag the voltage by 90°

Question 3

Capacitors for power factor correction are rated in

Accepted Answer

kVAR

Answer

kW

Answer

kVA

Answer

kV

Question 4

The power consumed in a circuit element will be least when the phase difference between the current and voltage is

Accepted Answer

90°

Answer

180°

Answer

60°

Answer

0°

Question 5

Which of the following statements pertains to resistors only?

Accepted Answer

Can dissipate considerable amount of power

Answer

Can act as energy storage devices

Answer

Connecting them in parallel increases the total value

Answer

Oppose sudden changes in voltage

Question 6

In a series L-C circuit at the resonant frequency the

Accepted Answer

Current is maximum

Answer

Current is minimum

Answer

Impedance is maximum

Answer

Voltage across C is minimum

Question 7

In a circuit containing R, L and C, power loss can take place in

Accepted Answer

R only

Answer

C only

Answer

L only

Answer

All above

Question 8

The best place to install a capacitor is

Accepted Answer

Across the terminals of the inductive load

Answer

Very near to inductive load

Answer

Far away from the inductive load

Answer

Any where

Question 9

All definitions of power factor of a series R-L-C circuit are correct except

Accepted Answer

Ratio of net reactance and impedance

Answer

Ratio of kW and kVA

Answer

Ratio of J and Z

Answer

Ratio of W and VA