Question

If a light ray incidents normally on one of the faces of the prism of refractive index $2$ and the emergent ray just grazes the second face of the prism, then the angle of deviation is

• A. $0^o$
• B. ${30}^o$
• C. ${45}^o$
• D. ${60}^o$

Answer 1

The correct option is B ${30}^o$

$\begin{array}{c}{Q}_c={\sin }^{-1}\frac{1}{2}\\ =\frac{\pi }{6}\end{array}$

$={30}^0$

Hence, Option $B$ is correct.