ISCET AC Circuits and Analysis 2

Question 1

In a series RLC circuit at resonance, what happens to the impedance?

Accepted Answer

Impedance equals the resistance R

Answer

Impedance equals infinity

Answer

Impedance equals zero

Answer

Impedance equals XL + XC

Question 2

What is the phase angle between voltage and current in a purely capacitive AC circuit?

Accepted Answer

Current leads voltage by 90°

Answer

Voltage leads current by 90°

Answer

Current and voltage are in phase

Answer

Current lags voltage by 45°

Question 3

If the frequency of an AC signal doubles, what happens to the capacitive reactance (XC)?

Accepted Answer

XC halves

Answer

XC doubles

Answer

XC quadruples

Answer

XC remains the same

Question 4

The power factor of an AC circuit is defined as:

Accepted Answer

True power divided by apparent power

Answer

Apparent power divided by true power

Answer

Reactive power divided by apparent power

Answer

True power divided by reactive power

Question 5

A transformer has a primary winding of 200 turns and a secondary winding of 50 turns. If 120V AC is applied to the primary, what is the secondary voltage?

Accepted Answer

30V

Answer

480V

Answer

60V

Answer

240V

Question 6

In an AC circuit, reactive power is measured in:

Accepted Answer

Volt-amperes reactive (VAR)

Answer

Watts (W)

Answer

Volt-amperes (VA)

Answer

Decibels (dB)

Question 7

What is the resonant frequency of a series LC circuit with L = 10 mH and C = 10 µF?

Accepted Answer

approximately 503 Hz

Answer

approximately 1592 Hz

Answer

approximately 159 Hz

Answer

approximately 50 Hz