NCEES Electrical Circuits 5

Question 1

The transfer function H(s) = V_out(s)/V_in(s) of a simple RC low-pass filter (R in series, C to ground) is:

Accepted Answer

1/(1+sRC)

Answer

V_out = V_in × (1/sC)/(R + 1/sC) = V_in/(1 + sRC), giving H(s) = 1/(1+sRC).

Question 2

The bandwidth of a series RLC circuit with resonant frequency ω₀ = 5000 rad/s and Q = 25 is:

Accepted Answer

200 rad/s

Answer

Bandwidth BW = ω₀/Q = 5000/25 = 200 rad/s.

Question 3

In AC circuit analysis, the apparent power S is related to real power P and reactive power Q by:

Accepted Answer

|S|² = P² + Q²

Answer

The power triangle gives |S|² = P² + Q², where S is in VA, P in W, and Q in VAR.

Question 4

A 10 Ω resistor and a 10 Ω inductive reactance are connected in parallel. What is the magnitude of the equivalent impedance?

Accepted Answer

7.07 Ω

Answer

Z_eq = (10 × j10)/(10 + j10) = j100/(10+j10); |Z_eq| = 100/|10+j10| = 100/(10√2) = 10/√2 ≈ 7.07 Ω.

Question 5

Kirchhoff's Voltage Law (KVL) is a consequence of:

Accepted Answer

Conservation of energy

Answer

KVL states that the algebraic sum of voltages around any closed loop is zero, which follows from conservation of energy (work done around a closed path is zero).

NCEES Practice Test

NCEES Practice Test

NCEES Electrical Circuits 5