Speed of light in a medium of refractive index n:
- n c
- c × n²
- c / n (light slows down in dense medium)
- c
Show answer and 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.