Question

A ray of light is incident on a right angled isosceles prism parallel to its base as shown in the figure. Refractive index of the material of the prism is $\sqrt{2}$. Then which of the following statement(s) is/are true?

• A. The reflection at P is total internal
• B. The reflection at Q is total internal
• C. The ray emerging at R is parallel to the ray incident at S
• D. Total deviation of the ray is ${150}^o$

Answer 1

Answer: (A), (C)

The correct options are
A The reflection at P is total internal
C The ray emerging at R is parallel to the ray incident at S

$1\cdot \sin i=\sqrt{2}\cdot \sin {15}^o$
$1\cdot \sin i=\sqrt{2}\left(\frac{\sqrt{3}-1}{2\sqrt{2}}\right)$
$\sin i=\frac{\sqrt{3}-1}{2}$
Ans: Ray will undergo TIR at P only Ans. (A)
If Ray emerge from R(Partially) it is possible, then it will become parallel to the incident Ray so ans (C).