A.C Fundamentals, Circuits and Circuit Theory MCQs

Question 1

The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of ________ degrees.

Accepted Answer

45

Answer

90

Answer

60

Answer

30

Question 2

The purpose of a parallel circuit resonance is to magnify

Accepted Answer

Voltage

Answer

Current

Answer

Power

Answer

Frequency

Question 3

The safest value of current the human body can carry for more than 3 second is

Accepted Answer

9 mA

Answer

4 mA

Answer

15 mA

Answer

25 mA

Question 4

In a highly capacitive circuit the

Accepted Answer

Reactive power is more than the actual power

Answer

Apparent power is equal to the actual power

Answer

Reactive power is more than the apparent power

Answer

Actual power is more than its reactive power

Question 5

An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms,

Accepted Answer

Both resistance and inductance carry equal currents

Answer

The current through the resistance is more

Answer

The current through the resistance is less

Answer

None of the above

Question 6

Poor power factor

Accepted Answer

Results in all above

Answer

Reduces load handling capability of electrical system

Answer

Results in more power losses in the electrical system

Answer

Overloads alternators, transformers and distribution lines

Question 7

Form factor for a sine wave is

Accepted Answer

1.11

Answer

1.414

Answer

0.707

Answer

0.637

Question 8

The frequency of domestic power supply in India is

Accepted Answer

50 Hz

Answer

200 Hz

Answer

100 Hz

Answer

60 Hz

Question 9

Pure inductive circuit

Accepted Answer

Takes power from the line during some part of the cycle and then returns back to it during other part of the cycle

Answer

Consumes some power on average

Answer

Does not take power at all from a line

Answer

None of the above