Lineman Electrical Theory and Principles

Question 1

According to Ohm's Law, if a circuit has a voltage of 120V and a resistance of 30 ohms, what is the current?

Accepted Answer

4 amps

Answer

Ohm's Law states I = V/R, so 120V ÷ 30Ω = 4 amps.

Question 2

What is the standard frequency of AC power in the United States?

Accepted Answer

60 Hz

Answer

The US power grid operates at 60 Hz, meaning the current alternates direction 60 times per second.

Question 3

Which of the following best describes power factor in an AC circuit?

Accepted Answer

The ratio of true power to apparent power

Answer

Power factor is the ratio of real (true) power (watts) to apparent power (volt-amperes), ranging from 0 to 1.

Question 4

In a series circuit, if one component fails (opens), what happens to the rest of the circuit?

Accepted Answer

The entire circuit stops conducting

Answer

In a series circuit, all components share the same current path, so an open in any one component interrupts current flow through the entire circuit.

Question 5

What is the relationship between frequency and period of an AC waveform?

Accepted Answer

Period = 1 / Frequency

Answer

Period (T) is the time for one complete cycle, and it equals 1 divided by frequency (f), expressed as T = 1/f.

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