allerySpeed of light in a medium of refractive index n:
An c
Bc × n²
Cc / n (light slows down in dense medium)
Dc
Answer & Solution
Correct answer: C. c / n (light slows down in dense medium)
v = c/n.
Higher n → slower light.
In water (n = 1.33): v ≈ 2.26 × 10⁸ m/s.
In glass (n ≈ 1.5): v ≈ 2 × 10⁸ m/s.
Refraction arises because of this speed change.
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