Question

The refractive index of water is 1.33. What will be the speed of light in water?

• A. $ 4 \times {10}^8 m/s $
• B. $ 1.33 \times {10}^8 m/s $
• C. $ 3 \times {10}^8 m/s $
• D. $ 2.25 \times {10}^8 m/s $

Answer 1

Answer: (D)

Refractive index of water $ ({\mu }_2) $ = 1.33.
$\frac{v_2}{v_1} = \frac{{\mu}_1}{{\mu}_2} = \frac{1}{1.33}$
therefore $ v_2 = \frac{v_1}{1.33} = \frac{3 \times {10}^8}{ 1.33} = 2.25 \times {10}^8 m/s $