Rainbow formation involves: MCQ with Answer and Explanation

Rainbow formation involves:
A. Diffraction
B. Refraction only
C. Reflection only
D. Dispersion and total internal reflection
Answer: Option D
Solution (By JKSSB Mock Tests)
Rainbow: sunlight enters raindrop (refraction + dispersion), reflects internally (TIR), exits with further refraction. Primary rainbow: one TIR; secondary: two TIRs. Memory tip: 'Rainbow = refraction + dispersion + TIR in water droplets'. Application question testing atmospheric optics, frequently appearing in competitive exams.

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Practice More Physics Questions

Question #1
The least count of a vernier calliper is 0.01 cm. A reading of 2.50 cm has how many significant figures?
A. 2
B. 3
C. 4
D. 1

Correct Answer: Option B


Explanation:
2.50 has three significant digits. Trailing zero after decimal significant because least count 0.01.

This question belongs to: Science Physics
Question #2
The nucleus of an atom contains
A. Electrons and neutrons
B. Electrons and protons
C. Only neutrons
D. Protons and neutrons

Correct Answer: Option D


Explanation:
Protons (positive), neutrons (neutral). Electrons orbit outside. Hydrogen nucleus only proton. Heavy elements have more neutrons.

This question belongs to: Science Physics
Question #3
A variable force F = (3x^2 + 2x) N acts on a particle. The work done by this force in moving the particle from x = 1 m to x = 2 m is:
A. 10 J
B. 12 J
C. 14 J
D. 16 J

Correct Answer: Option A


Explanation:
Work done by a variable force is the definite integral of F dx. W = Integral(3x^2 + 2x) dx from 1 to 2. W = [x^3 + x^2] evaluated from 1 to 2. Upper limit: (2^3 + 2^2) = 8 + 4 = 12. Lower limit: (1^3 + 1^2) = 1 + 1 = 2. Work = 12 - 2 = 10 Joules.

This question belongs to: Science Physics