question_answer

One of the refracting surfaces of a prism of angle of \[30{}^\circ \] is silvered. A ray of light incident at an angle of \[60{}^\circ \] retraces its path. The refractive index of the material of the prism is-

A) \[\sqrt{2}\]                                

B) \[\sqrt{3}\]

C) \[3/2\]               

D) \[2\]

Correct Answer: B

Solution :

\[1\,\,sin\,\,60{}^\circ =\mu \,\,sin\,30{}^\circ \]  \[\therefore \,\,\,\mu \,\,=\,\,\sqrt{3}\]