question_answer

A ray of light is incident normally on one face of a right angled isosceles prism. It then grazes the hypotenuse. The refractive index of the material of the prism is

A)  1.33                                      

B)  1.414

C)  1.5                                        

D)  1.732

Correct Answer: B

Solution :

Refractive index, \[\mu =\frac{1}{\sin \,C'}\] where C is the critical angle. Here,     \[C={{45}^{o}}\]               (as shown) \[\therefore \]  \[\mu =\frac{1}{\sin \,{{45}^{o}}}\] or            \[\mu =\sqrt{2}\] or            \[\mu =1.414\]