Question

under what conditions total internal reflection possible​

Answer 1

TIR only takes place when both of the following two conditions are met: the light is in the more dense medium and approaching the less dense medium. the angle of incidence is greater than the so-called critical angle.

Answer 2

Answer:

For total internal reflection to occur, two conditions must be met: The index of refraction must decrease across the boundary in the direction of light refraction. The angle of incidence of the light ray must exceed the critical angle of the interface.