A.C Fundamentals, Circuits and Circuit Theory MCQs

Question 1

A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to

Accepted Answer

The statement is incorrect

Answer

The capacitive reactance in ohms

Answer

The current flowing in capacitor

Answer

The size of the capacitor being quite big

Question 2

Time constant of a capacitive circuit

Accepted Answer

Increase with increase of capacitance and increase of resistance

Answer

Increases with the decrease of capacitance and decrease of resistance

Answer

Increases with the decrease of capacitance and increase of resistance

Answer

Increases with the increase of capacitance and decrease of resistance

Question 3

Capacitive reactance is more when

Accepted Answer

Capacitance is less and frequency of supply is less

Answer

Capacitance is less and frequency of supply is more

Answer

Capacitance is more and frequency of supply is less

Answer

Capacitance is more and frequency of supply is more

Question 4

The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that

Accepted Answer

Both waves must have same frequency

Answer

Both waves must have identical peak values

Answer

Both waves must have zero value at the same time

Answer

None of the above

Question 5

A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to

Accepted Answer

r.m.s. voltage

Answer

Average voltage

Answer

Peak voltage

Answer

None of the above

Question 6

In the case of an unsymmetrical alternating current the average value must always be taken over

Accepted Answer

The whole cycle

Answer

Unsymmetrical part of the wave form

Answer

The quarter cycle

Answer

The half cycle

Question 7

Time constant of an inductive circuit

Accepted Answer

Increases with increase of inductance and decrease of resistance

Answer

Increases with the increase of inductance and the increase of resistance

Answer

Increases with the decrease of inductance and decrease of resistance

Answer

Increases with decrease of inductance and increase of resistance

Question 8

Capacitive susceptance is a measure of

Accepted Answer

A purely capacitive circuit's ability to pass current

Answer

Reactive power in a circuit

Answer

The extent of neutralization of reactive power in a circuit

Answer

A purely capacitive circuit's ability to resist the flow of current

Question 9

The double energy transient occur in the

Accepted Answer

R-L-C circuit

Answer

Purely inductive circuit

Answer

R-L circuit

Answer

R-C circuit