Licensed Electrical Contractor Electrical Theory & Fundamentals 3

Question 1

What is the formula for calculating electrical power in a DC circuit?

Accepted Answer

P = V × I

Answer

P = V / I

Answer

P = V + I

Answer

P = V² × I

Question 2

What is the phase relationship between voltage and current in a purely inductive circuit?

Accepted Answer

Current lags voltage by 90°

Answer

Current leads voltage by 90°

Answer

Voltage and current are in phase

Answer

Current lags voltage by 45°

Question 3

What is the term for the total opposition to current flow in an AC circuit, combining resistance and reactance?

Accepted Answer

Impedance

Answer

Conductance

Answer

Admittance

Answer

Susceptance

Question 4

A 120V source is connected to a 20-ohm resistor. What is the current flowing through the circuit?

Accepted Answer

6 A

Answer

2,400 A

Answer

100 A

Answer

0.17 A

Question 5

What property of a material determines how well it conducts electricity?

Accepted Answer

Resistivity

Answer

Permeability

Answer

Permittivity

Answer

Reluctance

Question 6

In a series RLC circuit at resonance, what is true about the impedance?

Accepted Answer

Inductive and capacitive reactances cancel, leaving only resistance

Answer

Impedance is at its maximum value

Answer

Capacitive reactance dominates

Answer

Resistance drops to zero

Question 7

What is the effect of doubling the voltage in a circuit while keeping resistance constant?

Accepted Answer

Current doubles and power quadruples

Answer

Current halves and power stays the same

Answer

Current doubles and power doubles

Answer

Current stays the same and power doubles