Total internal reflection of light is possible when light enters from..............?

Hint: Total internal reflection can be given as the process that takes place when the light rays travel from a more optically denser medium to a less optically denser medium. Though the light travels from an optically denser to a rarer medium, the angle of refraction is more than the angle of incidence and it will keep on increasing as the angle of incidence is increased.

Complete answer:
Let us consider the following condition. A light ray that passes from a medium of water to that of air. This light ray is refracted at the point which is separating the two media. As it is moving from a medium of a higher refractive index to a lower refractive index, the refracted light ray curves away from the normal. At a certain angle of incidence, the incident ray of light is refracted in a way that it moves along the surface of the water. This definite angle of incidence is called the critical angle. The refraction angle is 90 degrees. When the angle of incidence becomes greater than the critical angle, the incident ray is reflected in the medium. We call this process total internal reflection. For total internal reflection to happen light must move from denser medium to rarer medium.

Total internal reflection of light is possible when light enters from water to air that means from denser to rarer medium.

Note:
Examples of Total Internal Reflection are as follows:
-In materials like diamonds, the shining is detected because of the several total internal reflections of light.
-Mirage: This happens because of the changing densities of the atmosphere close to the surface.
-Optical Fibres: Light is flung at an angle more than the critical angle so that the light passing through the fibers undergo Total internal reflection.