NEET-XII-Physics
neet 2020 questions with solutions year:2020
- #5A ray is incident at an angle of incidence `` i `` on one surface of a small angle prism(with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is `` \mu `` . then the angle of incidence is nearly equal to:
(A) `` \frac {A}{2\mu} ``
(B) `` \frac {2A}{\mu} ``
(C) `` \mu A ``
(D) `` \frac {\mu \,A}{2} ``
digAnsr: CAns : Light ray emerges from another surface normally, hence e(angle of emergence) = 0
`` \Rightarrow r_{2}=0 ``
`` r_{1}+r_{2}=A ``
`` \Rightarrow r_{1}=A ``
Applying Snell’s law on first surface,
`` 1. sin\,i=\mu\,sin\,r_{1} ``
For small angle , `` sin\,\theta\, \approx\,\theta `` Hence,
`` i=\mu\,A ``