The superposition theorem can be applied to find which of the following in a circuit?
Answer: B
Superposition theorem applies to linear networks and can be used to find voltage and current, but NOT power (since power is non-linear function).
Q.82Easy
In a planar circuit with B branches, N nodes, and L independent loops, the relationship between them is given by:
Answer: A
This is Euler's formula for planar networks: Number of independent loops (L) = Number of branches (B) - Number of nodes (N) + 1. This is fundamental in mesh analysis.
Q.83Medium
For a two-port network, if Z-parameters are known, the relationship between input impedance and Z11 is:
Answer: C
Z11 is defined as input impedance with port 2 open-circuited (I2=0). Therefore, Zin = Z11 only under this condition.
Q.84Medium
In a circuit with a dependent voltage source controlled by current, the controlling current flows through:
Answer: C
A CCVS (Current-Controlled Voltage Source) depends on current through any element in the control branch, measured in the specified reference direction.
Q.85Medium
Which method is most suitable for analyzing a circuit containing multiple independent and dependent sources?
Answer: C
Both nodal and mesh analysis can handle dependent sources. The choice depends on circuit configuration - nodal for current sources, mesh for voltage sources.
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Q.86Medium
The Thevenin equivalent resistance (RTh) of a network is found by:
Answer: D
RTh is calculated by replacing independent voltage sources with short circuits and independent current sources with open circuits, while keeping dependent sources intact.
Q.87Easy
In mesh analysis, for a circuit with 'm' meshes, the number of independent mesh equations is:
Answer: A
Number of independent mesh equations equals the number of independent loops (meshes) in the circuit. For m meshes, we need exactly m independent KVL equations.
Q.88Medium
A network is reciprocal if the transfer impedance Z12 equals Z21. This property holds for networks containing:
Answer: B
Reciprocity theorem applies to linear passive networks without dependent sources. If Z12 = Z21, then a voltage at port 1 producing current at port 2 equals the reverse situation.
Q.89Medium
In a circuit with time-varying sources, Kirchhoff's current law states that the algebraic sum of currents at a node is:
Answer: C
KCL is based on charge conservation and applies at ALL times - steady state and transients both. It's independent of whether sources are constant or time-varying.
Q.90Medium
For a two-port network with H-parameters (hybrid parameters), H21 represents:
Answer: B
H21 = I2/I1 (with V2=0) is the current transfer ratio or short-circuit current gain in a two-port network using hybrid parameters.
Q.91Hard
In a circuit with mutual inductance M between two coils, if the coupling coefficient k = 0.8, L1 = 10H, then L2 is at least:
Answer: A
Coupling coefficient k = M/√(L1·L2). For k=0.8 and L1=10H: 0.8 = M/√(10·L2). Since M ≤ √(L1·L2), we get L2 ≥ (M/k)²/L1 = (10·k²)/k² = L1/k² = 010.64 = 15.625H minimum requires M evaluation, but using k = M/√(L1L2) ≤ 1 gives L2 ≥ 6.25H.
Q.92Hard
A circuit has a loop containing 5V source, 10V source (opposite polarity), 2Ω, and 3Ω resistors. Using KVL, the current magnitude in the loop is:
Answer: A
Applying KVL around loop: 5 - 10 + 2I + 3I = 0 (taking voltages in one direction). This gives -5 + 5I = 0, so I = 1A.
Q.93Hard
In ABCD parameters of a two-port network, parameter C represents:
Answer: B
In ABCD parameters: V1 = AV2 - BI2; I1 = CV2 - DI2. C = I1/V2 (with I2=0) is the forward transadmittance with dimensions of admittance (Siemens).
Q.94Medium
For a circuit under steady-state AC conditions, the impedance of a 5H inductor at 50Hz frequency is approximately:
Answer: A
XL = 2πfL = 2π(50)(5) = 500π ≈ 1570.8Ω. For pure inductor, impedance is purely reactive with magnitude 1570.8Ω.
Q.95Easy
In a linear circuit with three independent loops, the number of independent mesh equations required for complete analysis is:
Answer: A
For a circuit with m independent loops (meshes), exactly m independent mesh equations are required. Each mesh contributes one independent equation. Therefore, for 3 loops, 3 equations are needed.
