Q. Refractive index of glass is $\frac{3}{2}$ and refractive index of water is $\frac{4}{3}$. If the speed of light in glass is $2.00 \times 10^{8}\ $m/s, the speed in water will be
A) $2.67 \times 10^{8}\ m/s$
B) $2.25 \times 10^{8}\ m/s$
C) $1.78 \times 10^{8}\ m/s$
D) $1.50 \times 10^{8}\ m/s$
Explanation
(b) $\mu \propto \frac{1}{v} \Rightarrow \frac{\mu_{g}}{\mu_{w}} = \frac{v_{w}}{v_{g}} \Rightarrow \frac{3/2}{4/3} = \frac{v_{w}}{2 \times 10^{8}}$
$\Rightarrow v_{w} = 2.25 \times 10^{8}m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.