In a synchronous buck converter, if the duty cycle is 0.7 and the switching frequency is 500kHz, what is the approximate inductor ripple current (ΔIL) with input voltage 48V and output voltage 24V?

The correct answer is B: 2.4A. ΔIL = (Vin × D × (1-D))/(L × f). Assuming standard inductor ~10μH: ΔIL ≈ (48 × 0.7 × 0.3)/(10e-6 × 500e3) ≈ 2.4A.

The sensitivity of a galvanometer is defined as:

The correct answer is A: Deflection per unit current. Sensitivity of a galvanometer is the deflection (in mm or degrees) produced per unit current (usually per microampere or milliampere).

In asynchronous sequential circuits, what is the primary concern regarding state transitions?

The correct answer is B: Race conditions and hazards that may cause incorrect state transitions. Asynchronous circuits lack global clock, so multiple state variables can change simultaneously, causing race conditions and hazards if not carefully designed.

The phenomenon of voltage instability leading to voltage collapse occurs primarily due to:

The correct answer is A: Insufficient reactive power support and high reactive power demand. Voltage collapse occurs when reactive power demand exceeds supply, causing progressive voltage reduction that destabilizes the system, as seen in 2012 Indian blackout.

Which compensation technique is used to improve steady-state accuracy?

The correct answer is B: Lag compensation. Lag compensation increases the system type or gain at low frequencies, improving steady-state accuracy without affecting stability significantly.

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Electrical Engg (EEE)
Electrical Measurements

Electrical machines, power systems, circuits

7 Q 7 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–7 of 7

Topics in Electrical Engg (EEE)

All Circuit Analysis 100 Electrical Machines 100 Power Systems 100 Control Systems 100 Power Electronics 100 Electrical Measurements 40 Digital Electronics 100

Q.1 Hard Electrical Measurements

A light intensity meter using a photocell shows reading of 500 lux. If the luminous intensity of the source is constant, what happens to the reading when distance is doubled?

A Becomes 250 lux

B Becomes 125 lux

C Becomes 1000 lux

D Remains 500 lux

Correct Answer: B. Becomes 125 lux

EXPLANATION

Illuminance follows inverse square law: E ∝ 1/d²; when distance doubles, illuminance becomes 1/4th: 500/4 = 125 lux.

Test

Q.2 Hard Electrical Measurements

In a three-phase power measurement using two-wattmeter method, the power factor can be determined from which relationship?

A tan(φ) = √3(W₁ - W₂)/(W₁ + W₂)

B cos(φ) = (W₁ + W₂)/√3VIL

C sin(φ) = (W₁ - W₂)/(W₁ + W₂)

D Power factor = (W₁ + W₂)/(W₁ - W₂)

Correct Answer: A. tan(φ) = √3(W₁ - W₂)/(W₁ + W₂)

EXPLANATION

For two-wattmeter method in three-phase systems: tan(φ) = √3(W₁ - W₂)/(W₁ + W₂), used to calculate power factor.

Test

Q.3 Hard Electrical Measurements

A strain gauge has gauge factor of 2.1 and resistance change of 5 Ω for a strain of 0.001. What is the original resistance of the gauge?

A 2300 Ω

B 2381 Ω

C 2500 Ω

D 2000 Ω

Correct Answer: B. 2381 Ω

EXPLANATION

Gauge factor = (ΔR/R₀)/strain; 2.1 = 5/(R₀ × 0.001); R₀ = 5/(2.1 × 0.001) ≈ 2381 Ω.

Test

Q.4 Hard Electrical Measurements

In a Kelvin's double bridge used for measuring low resistances (< 0.1 Ω), which configuration is adopted?

A Series arrangement of two arms

B Cross-connection between potential and current terminals

C Parallel-series hybrid configuration

D Bridge with four identical arms

Correct Answer: B. Cross-connection between potential and current terminals

EXPLANATION

Kelvin's double bridge uses cross-connection to eliminate lead resistance errors when measuring very low resistances in industrial applications.

Test

Q.5 Hard Electrical Measurements

In an AC bridge at balance condition, if R₁ = 100 Ω, R₂ = 50 Ω, and R₃ (inductive) = 200 Ω with series R, then R₄ is:

A 100 Ω

B 50 Ω

C 200 Ω

D 400 Ω

Correct Answer: A. 100 Ω

EXPLANATION

Using AC bridge balance: Z₁/Z₂ = Z₃/Z₄; therefore 100/50 = 200/Z₄, which gives Z₄ = 100 Ω

Test

Q.6 Hard Electrical Measurements

For accurate power measurement in a three-phase system with unbalanced load, the minimum number of wattmeters required is:

A 1

B 2

C 3

D 4

Correct Answer: C. 3

EXPLANATION

For unbalanced three-phase loads, three wattmeters are required—one in each phase—to measure total power accurately.

Test

Q.7 Hard Electrical Measurements

A voltmeter has an internal resistance of 100 kΩ and shows a reading of 50 V across a 1 MΩ resistor. What is the true voltage across the resistor?

A 45.45 V

B 50 V

C 54.55 V

D 60 V

Correct Answer: C. 54.55 V

EXPLANATION

The voltmeter and resistor form a parallel circuit. Using voltage divider: V_true = 50 × (1000 + 100) / 1000 ≈ 54.55 V

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Electrical Engg (EEE) Electrical Measurements

Electrical Engg (EEE)
Electrical Measurements