Question

What will be the minimum angle of incidence such that the total internal reflection occurs on both the surfaces?

Answer 1

Answer:

The answer will be 60° as for upper part it will be 45° and for lower part it will be 60°.

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Explanation:

Answer 2

Answer:

The answer will be 60° as for upper part it will be 45° and for the lower part it will be 60°.

Explanation:

Strictly speaking, critical angle means the angle of refraction is 90 degrees parallel to the interface, and it's just beyond that that you get the total internal reflection. So this represents basically the border and we'll call that the minimum angle such that you get this total internal reflection.