The device that protects electrical circuits from overload is MCQ with Answer and Explanation

The device that protects electrical circuits from overload is
A. Fuse
B. Switch
C. Capacitor
D. Resistor
Answer: Option A
Solution (By JKSSB Mock Tests)
Fuse melts and breaks circuit when current exceeds rating. MCB (Miniature Circuit Breaker) does same but resettable. Switch only turns on/off. Resistor limits current but doesn't break.

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Practice More Physics Questions

Question #1
Series LCR at resonance: impedance is:
A. Minimum (=R)
B. Maximum
C. Zero
D. Infinite

Correct Answer: Option A


Explanation:
Resonance: X_L = X_C ⇒ they cancel ⇒ Z = R (minimum). Current maximum at resonance. Memory tip: 'Series resonance: Z_min = R; parallel: Z_max'. AC circuit concept frequently tested in competitive exams.

This question belongs to: Science Physics
Question #2
The principle of AC generator is
A. Electromagnetic induction
B. Mutual induction
C. Self induction
D. Thermoelectric effect

Correct Answer: Option A


Explanation:
Changing flux induces emf.

This question belongs to: Science Physics
Question #3
A 60 W bulb is used for 5 hours daily. How much electrical energy is consumed by the bulb in 30 days?
A. 90 kWh
B. 900 kWh
C. 0.9 kWh
D. 9 kWh

Correct Answer: Option D


Explanation:
Electrical energy (E) = Power (P) × Time (t). Power = 60 W = 0.06 kW. Time per day = 5 hours. Total time in 30 days = 5 × 30 = 150 hours. Energy = 0.06 kW × 150 h = 9 kWh (or 9 units of electricity). One kWh is the commercial unit of energy.

This question belongs to: Science Physics