CEA Electrical Theory & Fundamentals 5

Question 1

A 1,500 W electric heater operates for 8 hours. How many kWh does it consume?

Accepted Answer

12 kWh

Answer

Energy = Power × Time = 1.5 kW × 8 h = 12 kWh.

Question 2

Which of the following best describes semiconductors?

Accepted Answer

Materials with conductivity between conductors and insulators

Answer

Semiconductors like silicon have electrical conductivity that can be controlled, placing them between conductors and insulators.

Question 3

What is the effect of doubling the cross-sectional area of a conductor while keeping length and material constant?

Accepted Answer

Resistance is halved

Answer

R = ρL/A; doubling area (A) halves resistance, allowing more current to flow.

Question 4

What voltage is typically found on a standard US residential 240V circuit?

Accepted Answer

Two 120 V legs that are 180° out of phase

Answer

US 240V service uses two 120V hot conductors that are 180° out of phase, producing 240V between them.

Question 5

What does the term 'electromotive force' (EMF) refer to?

Accepted Answer

The voltage produced by a source driving current through a circuit

Answer

EMF is the voltage generated by a source (battery, generator) that drives current around a circuit.

(CEA) Certified Electrical Apprentice Practice Test