💼 Official Mock Test for: ASSISTANT ENGINEER E&M (ELECTRICAL & MECHANICAL) (SPS-7)
⏱️ Official Timed Examination

ASSISTANT ENGINEER E&M (ELECTRICAL & MECHANICAL) (SPS-7) - Screening Mock Test 2026

Category: General Competitive

Duration
⏱️ 100 Mins
Question Pool
📝 100 MCQs
Passing Benchmark
🎯 50.0%
Scoring Engine
✓ Instant & Ranked

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Sample Questions & Solved Explanations

Representative sample from official examination pool

Below are representative questions drawn directly from the testing blueprint for this exam. Review these worked examples to understand the question style, difficulty calibration, and grading criteria:

Sample Q1 (Electrical Engineering) Difficulty: Easy
Kirchhoff's Current Law (KCL) at a junction in an electrical circuit is a direct mathematical consequence of which conservation law?
A Conservation of Energy
B Conservation of Electric Charge
C Conservation of Momentum
D Conservation of Magnetic Flux
✓ Answer: B - Conservation of Electric Charge
KCL states that the algebraic sum of currents entering a node is zero (ΣI = 0). Since current is the rate of flow of charge (dq/dt) and charge cannot accumulate at an infinitesimal node, KCL is based on the Conservation of Electric Charge.
Sample Q2 (Electrical Engineering) Difficulty: Easy
Kirchhoff's Voltage Law (KVL) around any closed loop is based on the principle of conservation of:
A Electric Charge
B Energy
C Power
D Mass
✓ Answer: B - Energy
KVL states that the algebraic sum of all voltages around any closed loop in a circuit must equal zero (ΣV = 0). Because electric potential is energy per unit charge (V = W/Q), moving a charge around a closed path and returning to the same point results in zero net work done, embodying Conservation of Energy.
Sample Q3 (Electrical Engineering) Difficulty: Medium
Thévenin's equivalent resistance (Rth) of a linear circuit containing independent and dependent sources is found by:
A Short-circuiting all voltage sources, open-circuiting all current sources, and calculating input impedance
B Connecting an external test source (1 V or 1 A) at the terminals after deactivating only independent sources
C Taking the ratio of open-circuit voltage to maximum rated loop current
D Short-circuiting independent current sources and open-circuiting independent voltage sources
✓ Answer: B - Connecting an external test source (1 V or 1 A) at the terminals after deactivating only independent sources
When dependent sources are present in the circuit, they cannot be turned off. To determine Rth, all independent sources are deactivated (voltage sources shorted, current sources opened), an external test source (Vtest or Itest) is applied at the output terminals, and Rth = Vtest / Itest is calculated.
Sample Q4 (Electrical Engineering) Difficulty: Easy
According to the Maximum Power Transfer Theorem, maximum power is transferred from a linear source network to a purely resistive load when:
A The load resistance is equal to zero
B The load resistance is infinitely large
C The load resistance equals the Thévenin equivalent resistance of the source (RL = Rth)
D The load resistance is half the Thévenin equivalent resistance (RL = 0.5 Rth)
✓ Answer: C - The load resistance equals the Thévenin equivalent resistance of the source (RL = Rth)
Differentiating load power P = I^2 * RL = [Vth / (Rth + RL)]^2 * RL with respect to RL and setting dP/dRL = 0 yields RL = Rth. At this condition, the maximum power transferred is Pmax = Vth^2 / (4 * Rth) with an efficiency of 50%.
Sample Q5 (Electrical Engineering) Difficulty: Medium
In an AC circuit where the load impedance ZL = RL + jXL is connected to a source with internal impedance Zth = Rth + jXth, the condition for maximum power transfer is:
A ZL = Zth
B ZL = Zth* (complex conjugate: RL = Rth and XL = -Xth)
C RL = |Zth| and XL = 0
D ZL = -Zth
✓ Answer: B - ZL = Zth* (complex conjugate: RL = Rth and XL = -Xth)
For an AC circuit with adjustable load resistance and reactance, maximum power is delivered to the load when the load impedance is the complex conjugate of the source impedance: ZL = Zth*, meaning RL = Rth and XL = -Xth (cancelling the net reactive component).
Sample Q6 (Electrical Engineering) Difficulty: Easy
Norton's equivalent circuit consists of:
A An ideal voltage source in series with an impedance
B An ideal current source in parallel with an impedance
C An ideal voltage source in parallel with an impedance
D An ideal current source in series with an impedance
✓ Answer: B - An ideal current source in parallel with an impedance
Norton's Theorem states that any linear, two-terminal circuit can be replaced by an equivalent circuit consisting of a Norton short-circuit current source (IN) connected in parallel with a Norton equivalent impedance (RN = Rth).
Sample Q7 (Electrical Engineering) Difficulty: Easy
The Superposition Theorem is applicable only to circuits that are:
A Non-linear and time-invariant
B Linear and bilateral
C Non-linear with passive elements only
D Unilateral and frequency-dependent
✓ Answer: B - Linear and bilateral
Superposition relies on the mathematical properties of homogeneity and additivity (linearity). Therefore, it is strictly applicable to linear and bilateral networks where response is directly proportional to excitation.
Sample Q8 (Electrical Engineering) Difficulty: Medium
Why cannot the Superposition Theorem be used directly to calculate electric power in a circuit?
A Power is a vector quantity
B Power is proportional to the square of current or voltage (P = I^2*R or V^2/R), making it a non-linear relationship
C Power in AC circuits has a reactive component
D Independent sources absorb power rather than deliver it
✓ Answer: B - Power is proportional to the square of current or voltage (P = I^2*R or V^2/R), making it a non-linear relationship
Power depends quadratically on current (I^2*R) or voltage (V^2/R). Because (I1 + I2)^2 != I1^2 + I2^2 due to the cross-term 2*I1*I2, power is a non-linear quantity, so Superposition cannot be applied directly to calculate power.
Sample Q9 (Electrical Engineering) Difficulty: Easy
In a series RLC circuit at resonance, the total circuit impedance is:
A Purely reactive and maximum
B Purely resistive and minimum (Z = R)
C Equal to zero
D Purely capacitive
✓ Answer: B - Purely resistive and minimum (Z = R)
At series resonance, the inductive reactance equals capacitive reactance (XL = XC), so net reactance is zero. The circuit impedance Z = sqrt(R^2 + (XL - XC)^2) simplifies to Z = R, which is its minimum possible value, leading to maximum current flow.
Sample Q10 (Electrical Engineering) Difficulty: Medium
In a parallel RLC resonant circuit, the net impedance at resonance is:
A Minimum and purely reactive
B Maximum and purely resistive (Dynamic Resistance L / (C*R))
C Zero
D Inductive
✓ Answer: B - Maximum and purely resistive (Dynamic Resistance L / (C*R))
In a parallel RLC circuit (antiresonance), the circulating current between L and C is high while the line current drawn from the supply is minimum. Thus, impedance is maximum and purely resistive, termed dynamic impedance Z_dyn = L / (C * R).