Question

Light enters from air into a given medium at an angle of $45^{\circ}$ with interface of the air-medium surface. After refraction, the light ray is deviated through an angle of $15^{\circ}$ from its original direction. The refractive index of the medium is :

• A. $1.732$
• B. $1.333$
• C. $1.414$
• D. $2.732$

Answer 1

Answer: (C)

$ i =45^{\circ} $
$ D = i - r$
$ 15^{\circ}=45- r \Rightarrow r =30^{\circ}$
$ n _1 \sin i = n _2 \text{sin r}$
$ 1 \sin 45^{\circ}=\mu \sin 30^{\circ}$
$ \frac{1}{\sqrt{2}}=\mu \frac{1}{2}$
$\mu=\sqrt{2}=1.414$