2019 Ray Optics and Optical InstrumentsTotal Internal Reflection Easy Question 35 of 89 in Ray Optics and Optical Instruments

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?

A $180^\circ$
B $0^\circ$
C equal to angle of incidence
D $90^\circ$

The answer is D.

Solution

When the angle of incidence equals the critical angle $i_C$, the refracted ray grazes along the surface of separation. So the angle of refraction is $90^\circ$.

Concept angle of refraction at the critical angle

Ray Optics and Optical Instruments in past papers

89 questions from this chapter have appeared across 25 exam years.