An electric bulb rated 220 V, 100 W is operated at 110 V. The power consumed is MCQ with Answer and Explanation

An electric bulb rated 220 V, 100 W is operated at 110 V. The power consumed is
A. 50 W
B. 12.5 W
C. 25 W
D. 100 W
Answer: Option C
Solution (By JKSSB Mock Tests)
Resistance R = V²/P = 220²/100 = 484 Ω. At 110 V, P = V²/R = 110²/484 = 12100/484 = 25 W. Assuming resistance constant. Power reduces to quarter when voltage halved (P ∝ V² for fixed R).

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Physics Questions

Question #1
In simple harmonic motion, acceleration is directly proportional to
A. Square of displacement
B. Displacement but opposite in direction
C. Velocity
D. Time

Correct Answer: Option B


Explanation:
In SHM, a = -ω²x, acceleration ∝ -displacement. Minus sign indicates direction towards mean position (restoring). Characteristic of SHM. Pendulum and spring-mass system exhibit SHM for small displacements.

This question belongs to: Science Physics
Question #2
A bullet of mass 20 g is fired with velocity 200 m/s. Its momentum is
A. 40 kg m/s
B. 0.4 kg m/s
C. 4000 kg m/s
D. 4 kg m/s

Correct Answer: Option D


Explanation:
Mass m = 20 g = 0.02 kg. Momentum p = m v = 0.02 × 200 = 4 kg m/s. Always convert mass to kg. Momentum unit kg·m/s.

This question belongs to: Science Physics
Question #3
The function of a fuse in a domestic circuit is to
A. Reduce current
B. Protect against short circuit and overload
C. Regulate voltage
D. Increase power factor

Correct Answer: Option B


Explanation:
Fuse is a safety device: thin wire melts when current exceeds safe limit due to short circuit or overload, breaking circuit. Prevents fire and appliance damage. Based on heating effect. MCB is modern alternative.

This question belongs to: Science Physics