Ray Optics and Optical Instruments - Result Question 8
8. In total internal reflection when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be angle of refraction?
[2019]
(a) $180^{\circ}$
(b) $0^{\circ}$
(c) equal to angle of incidence
(d) $90^{\circ}$
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Answer:
Correct Answer: 8. (d)
Solution:
- (d) For total internal reflection when $i=i_c$, then
refracted ray grazes with the surface. That means the angle of refraction $r=90^{\circ}$.