alleryThe refractive index of glass is 1.5. The speed of light in glass is:
A3 × 10⁸ m/s
B2 × 10⁸ m/s (since v = c/n = 3 × 10⁸ / 1.5)
C4.5 × 10⁸ m/s
D1.5 × 10⁸ m/s
Answer & Solution
Correct answer: B. 2 × 10⁸ m/s (since v = c/n = 3 × 10⁸ / 1.5)
We have **v = c/n.
That is **v = 3 × 10⁸ / 1.5.
So **v = 2 × 10⁸ m/s**.
Light travels slower in any normal medium than in vacuum.
*Note: violet light slows MORE than red (n_violet > n_red — dispersion).*
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