A.C Fundamentals, Circuits and Circuit Theory MCQs

Question 1

The frequency of an alternating current is

Accepted Answer

The number of waves passing through a point in one second

Answer

The speed with which the alternator runs

Answer

The number of cycles generated in one minute

Answer

The number of electrons passing through a point in one second

Question 2

For a sine wave with peak value Emax ___________ 8.30. the average value is

Accepted Answer

0.636 Emax

Answer

0.707 Emax

Answer

0.434 EWc

Answer

lAUEmax

Question 3

Ohm is unit of all of the following except

Accepted Answer

Capacitance

Answer

Inductive reactance

Answer

Capacitive reactance

Answer

Resistance

Question 4

If resistance is 20 ohms. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be

Accepted Answer

0.1 s

Answer

0.001 s

Answer

10 s

Answer

100 s

Question 5

In a loss-free R-L-C circuit the transient current is

Accepted Answer

Sinusoidal

Answer

Oscillating

Answer

Square wave

Answer

Non-oscillating

Question 6

Wire-wound resistors are unsuitable for use at high frequencies because they

Accepted Answer

Exhibit unwanted inductive and capacitive effects

Answer

Create more electrical noise

Answer

Are likely to melt under excessive eddy current heat

Answer

Consume more power

Question 7

The series and parallel resonance on L-C circuit' differs in that

Accepted Answer

Series resistance needs a low-resistance source for sharp rise in current

Answer

Series resonance needs a high-resistance source for sharp increase in current

Answer

Parallel resonance needs a low-resistance source for a sharp increase in impedance

Answer

Parallel resonance needs a low-resistance source for a sharp rise in line current

Question 8

At very low frequencies a series R-C circuit behaves as almost purely

Accepted Answer

Capacitive

Answer

Resistive

Answer

Inductive

Answer

None of the above

Question 9

In an A.C. circuit power is dissipated in

Accepted Answer

Resistance only

Answer

Inductance only

Answer

Capacitance only

Answer

None of the above