What is the practical use of total internal reflection?
The phenomenon is used in light pipes. The light pipe consists of a cylindrical rod of transparent plastic. Light enters at one end of the rod nearly normal to the end surface. Any part of this light which reaches the side walls will have an incident angle greater than the critical angle and therefore will not escape into the surrounding air. Instead, a succession of total reflections will carry it along the rod and it will finally emerge at the far end. Refraction by prisms – dispersion Thus far we have concentrated our attention on what happens to light as it enters glass or some other substance from air or it leaves glass into air. What happens when light goes from air into glass and then goes from glass back into air? To find out what happens we can make use of a glass block with parallel faces. Figure 8 shows the results of this experiment. Figure 8 A pencil of light that is incident on one side of the glass leaves the glass on the other side travelling parallel to the incident di
