Question

When i = 30; refractive angle is 90° so
total internal reflection occurs at i = ......​

Answer 1

Answer:

40

Explanation:

Critical angle is the incident angle for which the refracted ray just grazes the surface i.e., r = 90°

=> i = C = 30°

For total internal reflection to occur, i must be more than C => i>30°

Therefore, the correct option for this question will be 4) 40°