2. Impedance and admittance of R, L, C elements
3. Series and parallel AC circuit combinations
4. Nodal and mesh analysis in the phasor domain
5. Superposition, Thevenin and Norton equivalents for AC circuits
6. AC power: instantaneous, average, reactive, apparent, and power factor
7. Complex power, power factor correction, and maximum average power
transfer
8. Three-phase circuits: wye and delta configurations, balanced loads
9. Magnetically coupled circuits and ideal transformers
10. Frequency response, resonance, and filter characteristics
EEE 334 Circuits II Midterm Exam
1. In a sinusoidal steady-state circuit, the phasor representation of the voltage
v(t) = 170 cos(377t + 30°) V has a magnitude and angle of which of the
, following?
A. 170∠30° V
B. 120∠30° V
C. 170∠-30° V
D. 120∠60° V
✅ A. The phasor magnitude equals the peak amplitude 170 V and the angle
equals the phase 30°, since the cosine reference is used directly.
2. The impedance of an inductor with inductance L at angular frequency ω is
expressed in rectangular form as which of the following?
A. ωL + j0
B. 0 - jωL
C. 0 + jωL
D. 1/(jωL)
✅ C. Inductive impedance is Z = jωL, a positive imaginary value with zero
real part.
3. The impedance of a capacitor with capacitance C at angular frequency ω is
given by which expression in the phasor domain?
, A. jωC
B. 1/(jωC)
C. ωC + j0
D. 0 + jωC
✅ B. Capacitive impedance is Z = 1/(jωC) = -j/(ωC), a negative imaginary
value.
4. For a series RLC circuit operating below its resonant frequency, the overall
input impedance is best described as which of the following?
A. Purely resistive with zero reactance
B. Capacitive because the capacitive reactance dominates
C. Inductive because the inductive reactance dominates
D. Purely inductive with infinite reactance
✅ B. Below resonance, 1/(ωC) exceeds ωL, so the net reactance is
capacitive and impedance has a negative imaginary part.
5. Two impedances Z1 = 3 + j4 Ω and Z2 = 6 - j8 Ω are connected in parallel,
and the equivalent impedance is which of the following?
A. 9 - j4 Ω
, B. 2 + j0 Ω
C. 4.5 - j2 Ω
D. 1.5 + j2 Ω
✅ B. Z1Z2/(Z1+Z2) = (50∠-53.13°)/(9-j4) yields approximately 2 + j0 Ω, a
nearly resistive equivalent.
6. In phasor-domain nodal analysis of an AC circuit, the sum of currents
leaving a node is set equal to zero because of which fundamental principle?
A. Kirchhoff's voltage law applied around each loop
B. Kirchhoff's current law applied at the node
C. The superposition theorem applied to sources
D. The maximum power transfer theorem
✅ B. Nodal analysis enforces KCL at each node, and in phasor form
currents are complex quantities.
7. When applying mesh analysis to a phasor-domain circuit containing a
current source shared by two meshes, the most appropriate treatment is
which of the following?
A. Convert the current source to a voltage source always