question_answer

A ray of light is incident at an angle of incidence, i, on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is \[\mu ,\]the angle of incidence i, is nearly equal to

A) \[\mu A\]           

B)                        \[\frac{\mu A}{2}\]                        

C)                        \[A/\mu \]         

D)        \[A/2\mu \]

Correct Answer: A

Solution :

Refractive index \[\mu =\frac{\sin i}{\sin r}\]        \[\mu =\frac{\sin i}{\sin A}\] In case of small angle.                   \[\mu =\frac{i}{A}\]                 \[i=\mu A\]