Journeyman Electrician’s Exam Transformers and Electrical Theory 2

Question 1

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

Accepted Answer

1.0

Answer

A purely resistive circuit has voltage and current in phase (0° phase angle), resulting in a power factor of 1.0 (unity).

Question 2

Apparent power in an AC circuit is expressed in which unit?

Accepted Answer

Volt-amperes (VA)

Answer

Apparent power is the product of RMS voltage and RMS current expressed in volt-amperes (VA) or kilovolt-amperes (kVA).

Question 3

A circuit has 240V applied and draws 20 amperes. Using Ohm's Law, what is the circuit resistance?

Accepted Answer

12 ohms

Answer

R = V ÷ I = 240 ÷ 20 = 12 ohms.

Question 4

What is the correct formula for calculating true (real) power in a single-phase AC circuit?

Accepted Answer

P = V × I × PF

Answer

True power (watts) = Voltage × Current × Power Factor; omitting PF gives apparent power in VA, not real power.

Question 5

A series circuit has a resistance of 6 ohms and an inductive reactance of 8 ohms. What is the total impedance?

Accepted Answer

10 ohms

Answer

Z = √(R² + XL²) = √(6² + 8²) = √(36 + 64) = √100 = 10 ohms.

Journeyman Electrician’s Exam Practice Test