Question

Total Internal Reflection: Given that all the incident power is reflected, and that a transmitted wave still exists, describe total internal reflection in terms of the energy conservation.

Answer 1

Total internal reflection is the reflection of the incident light, which hits a medium boundary at an angle greater than the critical angle, relative to the surface. Total internal reflection takes place only when the following two conditions are satisfied:

1) The angle of incidence is greater than the critical angle

2)The ray of light travels from a denser medium to a rarer medium.

When a light wave passes through a boundary between two materials of different refractive indices, a part of the wave will be refracted at the surface of the boundary, and another part will be reflected.

If the angle of incidence of the light wave is greater than the critical angle, i.e. the incidence angle at which the light is refracted and travels along the boundary, then the light wave cannot pass via the boundary. Under this condition, the light is said to be totally reflected back internally.