Question

A ray of light $\left(R_{1}\right)$ is incident on a glass slab at an angle equal to critical angle of glass-air system. The refracted ray $\left(R_{2}\right)$ undergoes partial reflection and refraction at other surface of slab. The angle between the reflected ray $\left(R_{3}\right)$ and refracted ray $\left(R_{4}\right)$ is

• A. $45^\circ $
• B. $135^\circ $
• C. $105^\circ $
• D. $95^\circ $

Answer 1

Answer: (C)

$\frac{sin 45 ^\circ }{sin ⁡ \theta }=\sqrt{2}$
$\theta =30^\circ $
$\alpha =180^\circ -\left(30 ^\circ + 45 ^\circ \right)=105^\circ $