Sunlight travel time to Earth: MCQ with Answer and Explanation

Sunlight travel time to Earth:
A. 8 days
B. 8 hours
C. 8 minutes
D. 8 seconds
Answer: Option C
Solution (By JKSSB Mock Tests)
Distance ≈ 1.5×10¹¹ m, c = 3×10⁸ m/s ⇒ t = 500 s ≈ 8.3 min. Standard astronomical fact. Memory aid: 'Sunlight takes 8 minutes; we see Sun as it was 8 min ago'. Scale knowledge frequently tested in competitive exams.

Discuss this Question (0)

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

Practice More Physics Questions

Question #1
Which of the following uses the principle of electromagnetic induction?
A. Electric heater
B. Transformer
C. Fuse
D. Incandescent bulb

Correct Answer: Option B


Explanation:
Transformer, induction cooker, generator use induction. Heater and bulb use heating effect of current. Fuse melts by heat. Induction: changing magnetic field induces current.

This question belongs to: Science Physics
Question #2
Three resistors of 2Ω, 3Ω, and 6Ω are connected in parallel. The equivalent resistance is:
A.
B.
C. 0.5Ω
D. 11Ω

Correct Answer: Option B


Explanation:
For parallel combination: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ = 1/2 + 1/3 + 1/6 = (3+2+1)/6 = 6/6 = 1. Thus R_eq = 1Ω. Note: Equivalent resistance in parallel is always less than the smallest individual resistance (here 2Ω). Memory tip: 'Parallel: reciprocal sum; result < min(R)'. This standard calculation tests parallel resistance formula application, frequently appearing in competitive exams. Always simplify fractions carefully; common denominator method avoids errors. Verify: 1Ω < 2Ω, consistent with parallel behavior.

This question belongs to: Science Physics
Question #3
Which of the following is used as a moderator in nuclear reactor?
A. Cadmium
B. Boron
C. Graphite
D. Uranium

Correct Answer: Option C


Explanation:
Graphite, heavy water (D₂O), beryllium are moderators. Cadmium and boron are control rods (absorb neutrons). Uranium is fuel. Moderator slows neutrons.

This question belongs to: Science Physics