Practice # 6 AC Theory

Front

What does it mean for one waveform to 'lead' another waveform?

Back

It means that the waveform reaches its maximum or minimum value before the other waveform.

Front

What is the effective value of a sine wave a measure of?

Back

The heating effect of the sine wave.

Front

What advantages are realized by using AC in airplanes?

Back

The power requirements can be met more efficiently due to the increasing number of electrically operated units.

Front

What is an instantaneous value of voltage or current?

Back

It is the induced voltage or current flowing at any instant during a cycle.

Front

What occurs at 90° in a sine wave of voltage?

Back

The largest single positive value.

Front

What occurs at 270° in a sine wave of voltage?

Back

The largest single negative value.

Front

How is the peak value related to the effective value in a sine wave?

Back

The peak value is 1.41 times the effective value.

Front

What are the two true statements regarding the peak value and effective value of a sine wave?

Back

1. The largest single positive value occurs at 90°. 2. The largest single negative value occurs at 270°.

Front

What is the significance of the heating effect in AC circuits?

Back

It indicates the amount of power that can be effectively used to produce heat in a resistive load.

Front

How does AC power distribution benefit electrical systems?

Back

AC can be easily transformed to different voltage levels, making it more efficient for long-distance transmission.