### Wave Optics Question 5

#### Question 5 - 29 January - Shift 2

Unpolarised light is incident on the boundary between two dielectric media, whose dielectric constants are 2.8 (medium -1) and 6.8 (medium 2 ), respectively. To satisfy the condition, so that the reflected and refracted rays are perpendicular to each other, the angle of incidence should be $\tan ^{-1}(1+\frac{10}{\theta})^{\frac{1}{2}}$ the value of $\theta$ is

(Given for dielectric media, $\mu_r=1$ )

## Show Answer

#### Answer: (7)

#### Solution:

#### Formula: Laws of Refraction

$\mu_1=\sqrt{2.8 \times 1}=\sqrt{2.8}$

$ \mu_2=\sqrt{6.8 \times 1}=\sqrt{6.8} $

$\mu_1 \sin i=\mu_2 \cos i$

$\tan i=\frac{\mu_2}{\mu_1}=\sqrt{\frac{6.8}{2.8}}$

$\tan i=(\frac{2.8+4}{2.8})^{1 / 2}$

$i=\tan ^{-1}(1+\frac{10}{7})^{1 / 2}$

$\theta=7$ Ans.