Question

When a light ray moves from air to a transparent medium the angle of incidence and the angle of refraction are ${45}^{\circ }$ and ${30}^{\circ }$ respectively. Find the refractive index of this medium is

• A. $1.21$
• B. $1.42$
• C. $1.88$
• D. $2.42$

Answer 1

The correct option is B $1.42$

Given,

Angle of incidence $\angle i={45}^0$

Angle of refraction $\angle r={30}^0$

By Snell's law

$n=\frac{sini}{sinr}$, where $n$ is the refractive index of the medium.

$n=\frac{sin{45}^0}{sin{30}^0}=\sqrt{2}=1.42$