BEE Basic Electrical 5

Question 1

A 60 W lamp operates at 120 V. What is its resistance?

Accepted Answer

240 Ω

Answer

R = V²/P = (120)²/60 = 14400/60 = 240 Ω.

Question 2

In a star (Y) connected three-phase system, the relationship between line voltage (V_L) and phase voltage (V_ph) is:

Accepted Answer

V_L = √3 × V_ph

Answer

In a balanced Y connection, the line voltage is √3 times the phase voltage.

Question 3

Which instrument is used to measure electrical energy consumption?

Accepted Answer

Energy meter (kWh meter)

Answer

An energy meter (kilowatt-hour meter) integrates power over time to measure total energy consumed.

Question 4

The skin effect in conductors causes current to:

Accepted Answer

Concentrate near the surface at high frequencies

Answer

At high frequencies, AC current tends to flow near the conductor's outer surface, reducing the effective cross-sectional area.

Question 5

What is the reactive power in a circuit where V = 100 V, I = 5 A, and the power factor angle θ = 30°?

Accepted Answer

250 VAR

Answer

Q = V·I·sin θ = 100 × 5 × sin 30° = 500 × 0.5 = 250 VAR.

BEE - Bachelor of Electrical Engineering Practice Test