Question

explain total internal reflection when a light pass through different media ​

Answer 1

Well, when a light Ray passes through a denser medium and is incident to the surface of a rarer medium at an angle for which the angle of refraction in the rarer medium is 90°, then that corresponding angle of incidence is known as the critical angle.
We, all know that when a light Ray is incident at some nice acute angle, the light Ray refracts and some angle of refraction is formed.
However, remember that total internal reflection can occur only when a light Ray is passing from denser to rarer medium because in the other way round, the light Ray bends towards the normal to the interface and thus their refraction angle of 90° isn't feasible
So, total internal reflection is actually the phenomenon in which when a light passing through denser medium is incident on the rarer mediums surface at an angle greater than the corresponding critical angle, then the light Ray does not refract at all but completely reflects back into the same denser medium.
There are a lot of important applications of this amazing phenomenon
For example
1) Mirage effect
2) Working of periscope and optical fiber
3) Bright shine of diamonds !

Hope this helps you !