Alternating Current and Voltage

This is an MCQ-based quiz on Alternating Current and Voltage.

This includes current, voltage, power, and frequency.

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A sine wave with an rms value of 12 V is riding on a dc level of 18 V. The maximum value of the resulting waveform is

6 V 30 V 35 V 0 V

A sine wave of 15 kHz is changing at a faster rate than a sine wave with a frequency of

25 kHz 12 kHz 18 kHz 1.3 MHz

Sine wave A has a positive-going zero crossing at 45°. Sine wave B has a positive-going zero crossing at 60°. Which of the following statements is true?

Wave A leads wave B by 15° Wave A lags wave B by 15° Wave A leads wave B by 105° Wave A lags wave B by 105°

If the rms current through a 6.8 kΩ resistor is 8 mA, the rms voltage drop across the resistor is

5.44 V 54.4 V 7.07 V 8 V

A sinusoidal current has an rms value of 14 mA. The peak-to-peak value is

45.12 mA 16 mA 39.6 mA 22.6 mA

A pulse waveform has a high time of 8 ms and a pulse width of 32 ms. The duty cycle is

25% 50% 1% 100%

If the rms voltage drop across a 15 kΩ resistor is 16 V, the peak current through the resistor is

15 mA 1.5 mA 10 mA 1 mA

One sine wave has a positive-going zero crossing at 15° and another sine wave has a positive-going zero crossing at 55°. The phase angle between the two waveforms is

0° 45° 40° None of the above

If the peak of a sine wave is 13 V, the peak-to-peak value is

6.5 V 13 V 26 V None of the above

When a sine wave has a frequency of 100 Hz in 12 s it goes through

1/100 cycle 12 cycles 120 cycles 1,200 cycles

The peak value of a sine wave is equal to ____ the RMS value.

1.414 x 1.44 x 0.414 x None of the above

What do you mean by alter alternator?

An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. DC AC None of the above

What do you mean by Instantaneous Value?

The value of alternating voltage and current at an instant t. The value of direct current which produces the same heating effect in a given resistor as is produced by the given alternating current when passed for the same time. It is defined as that value of direct current which sends the same charge in a circuit in the same time as is sent by the given alternating current in its half time period. Maximum values of voltage and current in a cycle

In a series L, R, C, circuit which is connected to a.c. source. When resonance is obtained then net impedance Z will be _____.

Z = R Z = ωL -1/ωC Z = ωL Z = 1/ωC

In a series resonant circuit, the a.c. voltage across resistance R, inductance L and capacitance C are 5V, 10V and 10V, respectively. The a.c. voltage applied to the circuit will be _______.

20V 10V 5V 25V

Why can’t the DC ammeter measure an alternating current?

AC cannot pass through a DC ammeter AC changes its direction AC is virtual The average value of a complete cycle is zero

Which one is the reciprocal of impedance?

Admittance Inductance Reactance Conductance

Root Mean Square Value is ________.

Random Access Memory The value of direct current which produces the same heating effect in a given resistor as is produced by the given alternating current when passed for the same time. The value of alternating voltage and current at an instant t. None of the above

Most practical alternators generate electricity from _____.

A coil rotating within a magnetic field

A magnetic field rotating around fixed windings

A permanent magnet rotating within a varying electromagnetic field

None of the above

Transformer works on the principle of _____.

Convertor

Invertor

Mutual induction

Self-induction

Quiz/Test Summary

Title: Alternating Current and Voltage