Electrical Engineering questions for GATE, PSU recruitment and SSC JE draw from network theory, electrical machines, power systems, control systems, measurements and instrumentation, analog and digital electronics, and electromagnetic fields. Numerical answers include the formula used and the unit at each stage, which is where marks are commonly lost even when the approach is correct.
In a circuit analysis problem, the voltage across a 5Ω resistor is measured as 25V. Using Ohm's law, what is the current through the resistor?
Answer: B
Using Ohm's law: I = V/R = 525 = 5A
Q.27Easy
In nodal analysis, the number of independent node equations required for a circuit with 'n' nodes and one reference node is:
Answer: A
In nodal analysis, we need (n-1) independent equations where n is total number of nodes. One node is chosen as reference (ground) node.
Q.28Easy
For a linear network, the superposition theorem applies when the network contains:
Answer: D
Superposition theorem applies to linear networks with multiple independent sources. The response is the sum of individual source responses.
Q.29Easy
The Thevenin equivalent resistance (Rth) is found by:
Answer: D
Rth is calculated by deactivating all independent sources (short voltage sources, open current sources) and finding equivalent resistance seen from load terminals.
Q.30Easy
In a bridge circuit at balance condition, the product of opposite resistances are equal. This principle is known as:
Answer: C
At Wheatstone bridge balance: R₁/R₂ = R₄/R₃ or R₁×R₃ = R₂×R₄. No current flows through galvanometer.
Q.31Easy
A circuit has three meshes. Using mesh current analysis, the total number of mesh current variables are:
Answer: B
Number of mesh current variables equals the number of independent meshes in the circuit. For 3 independent meshes, we have 3 mesh currents (I₁, I₂, I₃).
Q.32Easy
A circuit element is said to be active if it:
Answer: B
Active elements (voltage/current sources) can supply power. Passive elements (R, L, C) can only dissipate or store energy.
Q.33Easy
For a network containing resistances and a single voltage source, if we open-circuit the source terminal, the circuit becomes:
Answer: B
Removing all independent sources leaves only passive elements (resistors), making the network passive with no energy supply capability.
Q.34Easy
In nodal analysis, the number of independent equations required to solve a circuit with 'n' nodes (excluding the reference node) is:
Answer: A
In nodal analysis, we need (n-1) independent KCL equations for n nodes, where one node is taken as reference (ground). This follows from the fact that one equation is dependent on others.
Q.35Easy
A voltage source of 10V with internal resistance 2Ω is connected to a load resistance of 8Ω. The maximum power transfer to the load occurs when load resistance is:
Answer: A
Maximum power transfer theorem states that maximum power is transferred when load resistance equals the Thevenin equivalent resistance of the source (2Ω in this case).
Q.36Easy
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.37Easy
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.38Easy
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.39Easy
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.
