1. When the angle of incidence is greater than the critical angle, the light ray is reflected into denser medium at interface. This phenomenon is called total internal reflection.
2. Total internal reflection is the main reason for brilliance of diamonds. The critical angle of a diamond is very low. So if a light ray enters a diamond it is very likely to undergo total internal reflection which makes the diamond shine.
3. Total internal reflection is the basic principle behind working of optical fibre. Because of the small radius of the fibre light going into it makes a nearly glancing incidence is greater than the critical angle and hence total internal reflection takes place. The light is thus transmitted along the fibre.
