Total reflection is possible

When light passes from an optically denser medium into an optically thinner medium, it is generally refracted at the interface between the two substances. However, if the angle of incidence is greater than the critical angle, the light is no longer refracted, but is reflected at the interface. This process is called total reflection.

Conditions:
1. The light changes from an optically denser to an optically thinner medium.
2. The angle of incidence is greater than the critical angle.

Remarks:
The medium in which the speed of light is optically denser less is!
The critical angle aG is calculated as follows:, where c1 the speed of light in the optically denser medium, c2 is the speed of light in the optically thinner medium.

Technical use:
Total reflection is used in fiber optic cables. They consist of a core with optically dense glass, which is encased in a material made of optically thin glass. Light that is radiated into the fiber is repeatedly reflected inwards at the interface between the two types of glass. The light cannot leave the fiber.

Applications: data transmission in the telephone network
Use in endoscopes for observation and lighting during operations