Ray Optics and Optical Instruments - Result Question 58
61. A ray of light is incident at an angle of incidence, $i$, on one face of 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: [2012]
(a) $\mu A$
(b) $\frac{\mu A}{2}$
(c) $\frac{A}{\mu}$
(d) $\frac{A}{2 \mu}$
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Answer:
Correct Answer: 61. (a)
Solution:
- (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
$i=\mu A$
