TIR Application

Description:

The sparkling of diamonds is due to total internal reflection. For diamond critical angle is 24.40^o. So maximum number of rays incident on the diamond are reflected back inside the diamond moreover the cutting of the diamonds is made such that the incident ray has an angle greater than its critical angle, hence light suffers total internal reflection number of times before it comes out and diamond appears very bright.

Mirage in sad and loaming in ocean both occur due to total internal reflection.

Turning of light using prism.

• Turning light by 180^o

  When light is incident normal to the base of prism it enters straight without deviation in the prism, but when it strikes the inclined surface of the prism it make an angle of 45^o with the normal which is greater than the critical angle of glass (41.14^o) and hence the light suffers total internal reflection twice in within the prism that results in turning of light by 180^o, as shown in figure −

• Turning light by 90^o

  When light is incident normal to prism it enters straight without deviation in the prism, but when it strikes the other surface of the prism it make an angle of 45^o with the normal which is greater than the critical angle of glass (41.14^o) and hence the light suffers total internal reflection within the prism that results in turning of light by 90^o , as shown in figure −

• Inverting light

  When light is incident on the prism it is refracted towards the base of the prism, and the prism can be adjusted in such a way that the light rays strike the base at an angle greater than the critical angle of glass (41.14^o) and hence the light suffers total internal reflection within the prism that results in inversion of light, as shown in figure −

• Optics fiber uses total internal reflection for transmission of signals. Optical fiber is made up of two materials, internal material is denser than the outer material. When light enters the optical fiber, it strike the internal surface of the material at an angle close to 90^o and obviously the critical angle for any medium cannot be equal or greater than 90^o, Hence light suffers total internal reflection within the optical fiber