AC Fundamentals MCQ Questions

AC Fundamentals MCQ Questions

When one wave attains maximum value the other is at zero value, then phase angle between two alternating waves of equal frequency will be

When one wave attains maximum value the other is at zero value, then phase angle between two alternating waves of equal frequency will be

1. 0°
2. 180°
3. 45°
4. 90°

Correct answer: 4. 90°

For a frequency of 200 Hz, the time period will be

For a frequency of 200 Hz, the time period will be

1. 0.0005 s
2. 0.005 s
3. 0.05 s
4. 0.5 s

Correct answer: 2. 0.005 s

When an alternating current passes through an ohmic resistance the electrical power converted into heat is

When an alternating current passes through an ohmic resistance the electrical power converted into heat is

1. Apparent power
2. True power
3. Reactive power
4. None of these

Correct answer: 2. True power

The time constant of the capacitive circuit is defined as the time during which voltage

The time constant of the capacitive circuit is defined as the time during which voltage

1. Falls to 36.8% of its final steady value
2. Rises to 38.6% of its final steady value
3. Rises to 63.2% of its final steady value
4. None of these

Correct answer: 3. Rises to 63.2% of its final steady value

The frequency of an alternating current is defined as

The frequency of an alternating current is defined as

1. The number of cycles generated in one minute
2. The number of electrons passing through a point in one second
3. The number of waves passing through a point in one second
4. The speed with which the alternator runs

Correct answer: 3. The number of waves passing through a point in one second

A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be credited to

A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be credited to

1. The big size of the inductor
2. The current flowing in the inductor
3. The reactance of the inductor
4. The statement given is false

Correct answer: 4. The statement given is false

At very low frequencies a series RC circuit behaves as almost purely

At very low frequencies a series RC circuit behaves as almost purely

1. Resistive
2. Inductive
3. Capacitive
4. None of these

Correct answer: 3. Capacitive

In pure inductive circuit

In pure inductive circuit

1. Current can lead or lag by 90°
2. Current is in phase with voltage
3. Current lags behind voltage by 90°
4. Current leads voltage by 90°

Correct answer: 3. Current lags behind voltage by 90°

RMS value and mean value will be same in the case of

RMS value and mean value will be same in the case of

1. Half wave rectified sine wave
2. Sine wave
3. Square wave
4. Triangular wave

Correct answer: 3. Square wave

In a parallel R-C circuit, the current always

In a parallel R-C circuit, the current always

1. Lags applied voltage
2. Leads applied voltage
3. Remains in phase with applied voltage
4. None of these

Correct answer: 2. Leads applied voltage