GROL Power Sources and Distribution 2

Question 1

What is the power factor of a purely resistive AC circuit?

Accepted Answer

1.0 (voltage and current in phase)

Answer

0 (no real power consumed)

Answer

0.5 (half of apparent power)

Answer

0.707 (unity of reactive component)

Question 2

A transformer with a primary-to-secondary turns ratio of 1:2 connected to 120V AC will produce what secondary voltage?

Accepted Answer

240V, stepping up the voltage

Answer

60V, stepping down the voltage

Answer

120V, maintaining the same voltage

Answer

480V, doubling the ratio twice

Question 3

What happens to capacitive reactance (Xc) as the frequency of the applied AC signal increases?

Accepted Answer

Xc decreases as frequency increases

Answer

Xc increases proportionally with frequency

Answer

Xc remains constant regardless of frequency

Answer

Xc becomes purely resistive at high frequencies

Question 4

In a balanced three-phase power system, what is the phase angle difference between each of the three voltage waveforms?

Accepted Answer

120 degrees

Answer

60 degrees

Answer

180 degrees

Answer

90 degrees

Question 5

What is the primary role of the neutral conductor in a single-phase 120/240V AC distribution system?

Accepted Answer

To carry return current and establish a stable voltage reference point

Answer

To provide a path exclusively for ground fault currents

Answer

To protect equipment from lightning-induced surges

Answer

To regulate power factor for connected loads

Question 6

In a three-phase delta-connected system, what is the relationship between line current and phase current?

Accepted Answer

Line current equals phase current multiplied by √3

Answer

Line current equals phase current

Answer

Line current equals phase current divided by √3

Answer

Line current equals twice the phase current

Question 7

In a three-phase wye-connected system, what is the relationship between line voltage and phase voltage?

Accepted Answer

Line voltage equals phase voltage multiplied by √3

Answer

Line voltage equals phase voltage

Answer

Line voltage equals phase voltage divided by √3

Answer

Line voltage equals twice the phase voltage