BEE Fundamental Circuit Analysis 5

Question 1

A delta (Δ) network has resistors R_AB = 30 Ω, R_BC = 30 Ω, R_CA = 30 Ω. What is the equivalent star (Y) resistance at each node?

Accepted Answer

10 Ω

Answer

For a balanced delta, R_Y = R_Δ / 3 = 30 / 3 = 10 Ω at each node.

Question 2

If the frequency of an AC source doubles, the inductive reactance X_L:

Accepted Answer

Doubles

Answer

X_L = 2πfL, so X_L is directly proportional to frequency — doubling f doubles X_L.

Question 3

In a circuit, a dependent voltage source whose value is controlled by a current elsewhere is called a:

Accepted Answer

Current-controlled voltage source (CCVS)

Answer

A CCVS (transresistance source) produces a voltage proportional to a controlling current in another branch.

Question 4

What is the resonant frequency of a series RLC circuit with L = 10 mH and C = 40 µF?

Accepted Answer

251.6 Hz

Answer

f_0 = 1/(2π√LC) = 1/(2π√(0.01×40×10⁻⁶)) = 1/(2π×0.000632) ≈ 251.6 Hz.

Question 5

When applying the current divider rule, the current through branch R1 in a parallel circuit is:

Accepted Answer

I_total × R2/(R1+R2)

Answer

The current divider gives I_R1 = I_total × R2/(R1+R2) — the branch with lower resistance carries more current.

BEE - Bachelor of Electrical Engineering Practice Test