A light ray enters from air into glass. How does its speed, frequency, and wavelength change? MCQ with Answer and Explanation

A light ray enters from air into glass. How does its speed, frequency, and wavelength change?
A. Speed increases, frequency remains same, wavelength increases.
B. Speed decreases, frequency remains same, wavelength decreases.
C. Speed decreases, frequency decreases, wavelength decreases.
D. Speed remains same, frequency decreases, wavelength increases.
Answer: Option B
Solution (By JKSSB Mock Tests)
When light passes from a rarer medium (air) to a denser medium (glass), its speed decreases due to the higher refractive index. Wavelength is directly proportional to speed, so it also decreases. However, the frequency depends only on the source of light and remains absolutely constant during refraction across any boundary.

Discuss this Question (0)

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

Practice More Physics Questions

Question #1
A satellite moves in a circular orbit around the Earth at a constant speed. The work done by the gravitational force on the satellite is:
A. Zero
B. Maximum
C. Negative
D. Positive

Correct Answer: Option A


Explanation:
Work is defined as W = F.d.cos(θ). For a satellite in a circular orbit, the gravitational force acts as the centripetal force, directing entirely towards the center of the Earth. The displacement of the satellite at any instant is tangential. Since the angle between force and displacement is exactly 90°, cos(90°) = 0, meaning zero work is done.

This question belongs to: Science Physics
Question #2
The device that converts mechanical energy into electrical energy is
A. Battery
B. Generator
C. Transformer
D. Motor

Correct Answer: Option B


Explanation:
Electric generator (dynamo/alternator) works on electromagnetic induction: mechanical rotation induces emf. Motor does opposite. Transformer changes voltage. Battery converts chemical to electrical.

This question belongs to: Science Physics
Question #3
Gamma rays are
A. Electromagnetic radiation of very high frequency
B. Fast electrons
C. Slow neutrons
D. Helium nuclei

Correct Answer: Option A


Explanation:
Gamma rays are photons, electromagnetic waves with wavelengths shorter than X-rays, produced in nuclear transitions. No mass, no charge. Highly penetrating. Stopped by thick lead.

This question belongs to: Science Physics