Alternating Current (26201-20)

A 20-microfarad capacitor is in parallel with a 10-microfarad capacitor. The total capacitance is

30 microfarads

A circuit has a peak voltage of 310V. What is the average voltage value?

197V

A device that uses electromagnetic induction to transfer electrical energy from one circuit to another is a(n)

transformer

According to the power triangle, the apparent power is

greater than the true power

Each of two equal capacitors in series has

half the applied voltage

If a transformer has 200 turns in the primary, 100 turns in the secondary, and 240VAC applied to the primary, the voltage across the secondary is

120VAC

If the phase angles of two sine waves are both 0 degrees, then the waves

are in phase

If the time for one cycle is 0.2 seconds, the frequency is

5Hz

In a circuit that has both capacitance and resistance, the current will lead the voltage

by some angle between 0° and 90°

One type of nonsinusoidal waveform is the

sawtooth wave

Opening the secondary circuit of a current transformer under load will cause a dangerous level of

induced high voltage

Reactive power is always

out of phase with true power

The opposing force that an inductor presents to the flow of alternating current is called

inductive reactance

The power factor can be defined as the ratio of true power to

apparent power

The product of the source voltage and the total current is

apparent power

The self-induced voltage across an inductance is produced by a change in current with respect to

time

Transformer windings are typically wrapped around a(n)

iron core

Transformers in which the primary and secondary voltages are 180 degrees out of phase are known as

unlike-wound transformers

What is the apparent power of an AC circuit with a source voltage of 120V and a total current of 6A?

720W

What is the apparent power of an AC circuit with a source voltage of 240V and a total current of 15A?

3,600W

What is the current flow in a purely resistive AC circuit if the resistance is 20 ohms and the voltage is 240V?

12A

What is the frequency of an AC waveform that completes 30 cycles per half second?

60Hz

What is the step-down turns ratio of a transformer with 150 turns in the primary and 50 turns in the secondary?

3:1

What is the step-up turns ratio of a transformer with 50 turns in the primary and 100 turns in the secondary?

1:2

What is the true power in a 2A series RL circuit with a 50Ω resistor?

200W