Deck 16: Alternating Current

Question 1

When current rises and falls at the same rate as the voltage and reverses the direction of flow when the voltage reverses polarity, the current is said to be with the voltage.

A) in phase
B) out of phase
C) in leading phase
D) in lagging phase

Answer 1

A

Question 2

Each complete waveform of 360° is called a .

A) cycle
B) hertz
C) frequency
D) rotation

Answer 2

A

Question 3

A term used to indicate the same value as the RMS value is the value.

A) average
B) peak
C) peak-to-peak
D) effective

Answer 3

D

Question 4

The amplitude of a waveform is measured from .

A) peak-to-peak
B) zero to the highest value obtained in either direction
C) zero to the RMS level
D) zero to the effective level

Question 5

The number of cycles completed in one second is called a .

A) cycle
B) hertz
C) frequency
D) rotation

Question 6

Square waves are generally produced by electronic devices called .

A) converters
B) alternators
C) oscillators
D) rectifiers

Question 7

The effect occurs when AC induces eddy currents into the conductor, which cause the electrons to be repelled toward the outer surface of the conductor.

A) insulation
B) phasing
C) skin
D) resistance

Question 8

Rotating machines normally produce a waveform called a wave.

A) cosine
B) linear
C) sine
D) pulsating

Question 9

If an AC waveform is rectified and converted into DC, the voltage value that results is the value.

A) average
B) peak
C) peak-to-peak
D) effective

Question 10

What type of load contains pure resistance?

A) capacitive
B) inductive
C) reactive
D) resistive

Question 11

When AC voltage is rectified and converted into DC, the resulting waveform is normally not pure, flat DC. The pulses that occur are called .

A) harmonics
B) cosines
C) ripples
D) peaks

Question 12

What type of AC waveform features voltage rising at a constant rate with respect to time?

A) cosine
B) linear
C) sine
D) pulsating

Question 13

What is the most common of all AC waveforms?

A) triangle
B) sine
C) pulsating
D) cosine

Question 14

The maximum point of a waveform is called the .

A) RMS
B) peak
C) peak-to-peak
D) effective

Question 15

What is the unit of measure for the power delivered to the load in a DC circuit?

A) hertz
B) volt-amperes
C) VARs
D) watts

Question 16

Both AC and DC can be transformed.

Question 17

What is the peak voltage of a 277 V RMS AC voltage?

A) 391.68 V
B) 434.85 V
C) 576.45 V
D) 695.90 V

Question 18

Frequency is measured in .

A) watts
B) hertz
C) amperes
D) voltage

Question 19

In a DC circuit, the product of volts times the amperes is called the power.

A) apparent
B) reactive
C) true
D) inductive

Question 20

What is the RMS value of an AC voltage that has a 480 V peak?

A) 278.72 V
B) 305.76 V
C) 339.46 V
D) 453.53 V

Question 21

To help overcome the problem of skin effect in high-frequency circuits, conductors with a large amount of
_______________ must be used.