Question

The adjoining figure shows the path of a light ray travelling from a transparent medium A to another transparent medium B. The refractive index of medium B w.r.t. A is

• A. $\sqrt{2}$
• B. $\frac{1}{\sqrt{2}}$
• C. $\sqrt{\frac{3}{2}}$
• D. $\sqrt{\frac{2}{3}}$

Answer 1

The correct option is A

$\sqrt{2}$

Step 1: Given data

Angle of incident, $\angle i=45°$

Angle of reflection, $\angle r=30°$

Refractive index, $n$

Step 2: Formula used and calculation

Refractive index is given by

$$\begin{gathered} n=\frac{\sin i}{\sin r} \\ n=\frac{\sin 45°}{\sin 30°} \\ n=\frac{{\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\sqrt{2}$}\right.}}{{\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}} \\ n=\sqrt{2} \end{gathered}$$

Hence, option (a) is correct.