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)

$2.25 \times {10}^8 m/s$

Answer 2

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