Question

what are the conditions for total internal reflection

Answer 1

Total Internal Reflection only takes place when both of the following two conditions are met;the light is in the more dense medium and approaching the lens dense medium.the angle of incidence is greater than the so called critical angle.

Answer 2

total internal reflection two three conditions must be met they are

the light must be travelling from a denser to rarer medium

angle of incidence must be larger than the critical angle

critical angle is nothing but the angle of incidence for which the angle of refraction is 90 degree