Q. 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) $A/2\mu$
Explanation
(a) For normally emerge $e = 0$
Therefore $r_{2} = 0$ and $r_{1} = A$
Snell’s law for incident ray’s
$1\sin i = \mu\sin r_{1} = \mu\sin A$
For small angle
$i = \mu\ A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.