A.C Fundamentals, Circuits and Circuit Theory MCQs

Question 1

The ratio of active power to apparent power is known as factor.

Accepted Answer

Power

Answer

Demand

Answer

Load

Answer

Form

Question 2

In a three-phase supply floating neutral is undesirable because it way give rise to

Accepted Answer

Unequal line voltages across the load

Answer

High voltage across the load

Answer

Low voltage across the load

Answer

None of these

Question 3

Power factor of electric bulb is

Accepted Answer

Unity

Answer

Zero

Answer

Lagging

Answer

Leading

Question 4

If two sine waves of the same frequency have a phase difference of JT radians, then

Accepted Answer

When one wave reaches its maxi¬mum value, the other will reach its minimum value

Answer

Both will reach their minimum values at the same instant

Answer

Both will reach their maximum values at the same instant

Answer

None of the above

Question 5

The power factor at resonance in R-L-C parallel circuit is

Accepted Answer

Unity

Answer

Zero

Answer

0.08 lagging

Answer

0.8 leading

Question 6

The period of a wave is

Accepted Answer

Time required to complete one cycle

Answer

The same as frequency

Answer

Expressed in amperes

Answer

None of the above

Question 7

Which of the following coil will have large resonant frequency?

Accepted Answer

A coil with low distributed capacitance

Answer

A coil with large resistance

Answer

A coil with low resistance

Answer

A coil with large distributed capacitance

Question 8

The r.m.s. value and mean value is the same in the case of

Accepted Answer

Square wave

Answer

Triangular wave

Answer

Sine wave

Answer

Half wave rectified sine wave

Question 9

Power factor of the system is kept high

Accepted Answer

Due to all above reasons

Answer

To reduce line losses

Answer

To maximize the utilization of the capacities of generators, lines and transformers

Answer

To reduce voltage regulation of the line