Unit 16 Summary

Question 1

Most of the electric power generated in the world is.

Answer 1

AC

Question 2

AC can be transformed.

Answer 2

and DC cannot

Question 3

AC reverses its direction of flow at

Answer 3

periodic intervals.

Question 4

The most common AC waveform is t

Answer 4

he sine wave.

Question 5

There are 360 Degrees in one

Answer 5

complete sine wave.

Question 6

What is Frequency

Answer 6

Frequency is measured in hertz (Hz).

Question 7

Sine waves are produced by

Answer 7

rotating machines.

Question 8

Frequency is measured in

Answer 8

hertz (Hz).

Question 9

The instantaneous voltage at any point on a sine wave is equal to

Answer 9

the peak, or maximum, voltage times the sine of the angle of rotation.

Question 10

The peak-to-peak voltage is the amount of voltage measured from the

Answer 10

positive-most peak to the negative-most peak.

Question 11

The peak value is the maximum amount of

Answer 11

voltage attained by the waveform.

Question 12

The RMS value of voltage will produce as much power as a like amount of DC voltage.

Answer 12

true

Question 13

The average value of voltage is used when an AC sine wave is changed into DC.

Answer 13

true

Question 14

The current and voltage in a pure resistive circuit are in phase with each other.

Answer 14

true

Question 15

True power, or watts, can be produced only when current and voltage are both positive or both negative.

Answer 15

true

Question 16

Resistance in AC circuits is characterized by the fact that the resistive part will produce heat.

Answer 16

true

Question 17

There are three basic types of AC loads:

Answer 17

resistive, inductive, and capacitive.

Question 18

The electrons in an AC circuit are forced toward the outside of the conductor by eddy current induction in the conductor itself.

Answer 18

true

Question 19

Skin effect is proportional to

Answer 19

frequency.

Question 20

Skin effect can be reduced by using conductors with a large surface area.

Answer 20

true

Question 21

1. What is the most common type of AC waveform?

Answer 21

Sign Wave

Question 22

2. How many degrees are there in one complete sine wave?

Answer 22

360 Degrees

Question 23

3. At what angle does the voltage reach its maximum negative value on a sine wave?

Answer 23

?

Question 24

4. What is frequency?

Answer 24

?

Question 25

5. A sine wave has a maximum value of 230 V. What is the voltage after 38 Degrees of rotation?

Answer 25

?

Question 26

6. A sine wave has a voltage of 63 V after 22 8 of rotation. What is the maxi-mum voltage reached by this waveform?

Answer 26

?

Question 27

7. A sine wave has a maximum value of 560 V. At what angle of rotation will the voltage reach a value of 123 V?

Answer 27

?

Question 28

8. A sine wave has a peak value of 433 V. What is the RMS value?

Answer 28

?

Question 29

9. A sine wave has a peak-to-peak value of 88 V. What is the average value?

Answer 29

?

Question 30

10. A DC voltage has an average value of 68 V. What is the RMS value?

Answer 30

?