Question

A ray of light falls on a transparent, right-angled isosceles prism made from a glass of refractive index $\sqrt{2}$ . The incident ray falls normally on one of the equal sides of this prism. The ray will suffer

• A. total internal reflection
• B. Interference
• C. refraction with angle of refraction $90{}^{\circ }$
• D. None of the above

Answer 1

Answer: (C)

Let the critical angle for air glass pair of media is given by c. Therefore, $\mu =\frac{1}{\sin C},\sqrt{2}=\frac{1}{\sin C}\Rightarrow C=45{}^{\circ }$ By geometry, angle of incidence at hypotenuse surface of transparent right-angled isosceles prism is $45{}^{\circ }$ . Therefore, $i=c=45{}^{\circ }$ Thus, total internal reflection doesnt occur as $i$ is not $>c$ . And. angle of refraction is $90{}^{\circ }$ .