NCEES Electrical Circuits 2

Question 1

A series RLC circuit has R = 10 Ω, L = 0.1 H, and C = 100 μF. What is the resonant frequency in rad/s?

Accepted Answer

100

Answer

Resonant frequency ω₀ = 1/√(LC) = 1/√(0.1 × 100×10⁻⁶) = 1/√(10⁻⁵) = 316 rad/s — wait, recalculating: √(0.1 × 100e-6) = √(10e-6) = 0.00316, so ω₀ = 316 rad/s.

Question 2

For a parallel RLC circuit at resonance, the impedance is:

Accepted Answer

Equal to R

Answer

At resonance in a parallel RLC circuit, the inductive and capacitive susceptances cancel, leaving impedance equal to R (the resistive branch).

Question 3

The quality factor Q of a series RLC circuit is defined as:

Accepted Answer

ωL/R

Answer

For a series RLC circuit, Q = ω₀L/R = 1/(ω₀RC), representing the ratio of reactive energy stored to energy dissipated per cycle.

Question 4

Two capacitors, C₁ = 4 μF and C₂ = 6 μF, are connected in series. What is the equivalent capacitance?

Accepted Answer

2.4 μF

Answer

Series capacitance: 1/C_eq = 1/4 + 1/6 = 5/12, so C_eq = 12/5 = 2.4 μF.

Question 5

In a purely inductive AC circuit, the current lags the voltage by:

Accepted Answer

90°

Answer

In a pure inductor, v = L(di/dt), which causes current to lag voltage by exactly 90°.

NCEES Practice Test

NCEES Practice Test

NCEES Electrical Circuits 2