Previous Year NEET Question- Wave Optics L-2

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

A) $4 \times 10^8 \mathrm{~m} / \mathrm{s}$

B) $1.33 \times 10^8 \mathrm{~m} / \mathrm{s}$

C) $3 \times 10^8 \mathrm{~m} / \mathrm{s}$

D) $2.25 \times 10^8 \mathrm{~m} / \mathrm{s}(1996)$

Answer: $2.25 \times 10^8 \mathrm{~m} / \mathrm{s}(1996)$#

Sol:#

Refractive index of water $\left(\mu_2\right)=1.33$. $$ \frac{v_2}{v_1}=\frac{\mu_1}{\mu_2}=\frac{1}{1.33} $$

Therefore $v_2=\frac{v_1}{1.33}=\frac{3 \times 10^8}{1.33}=2.25 \times 10^8 \mathrm{~m} / \mathrm{s}$