Light traveling in a medium of index of refraction n1 is incident on another medium having an index of refraction n2. Under which of the following conditions can total internal reflection occur at the interface of the two media? (Select all that apply.) The angle of incidence is greater than the critical angle. The angle of incidence is less than the critical angle. The indices of refraction have the relation n2 > n1. The indices of refraction have the relation n1 > n2. The light propagates at a greater speed in medium 1 than in medium 2.

Explanation:

Total internal reflections is a phenomenon where incident light rays when travelling from a denser medium or from a medium with higher refractive index to less dense medium or a medium  with lesser refractive index  ( The indices of refraction have the relation n₁ > n₂, where n₁ is the refractive index of the first medium and n₂ is the refractive index of medium 2) leads to the light ray being reflected back into the first medium instead of undergoing refraction. Usually, this occurs when the incident light rays angle to the normal is greater than a certain critical angle which is the angle when the refracted ray angle in the second medium is 90°