Optical Rarer medium and Optical Denser medium : A medium

Optically Rarer medium :

in which the speed of light is more is known as optically Rarer medium .

optically denser medium

A medium in which the speed of light is less , is known as optically denser medium.

Case 1. Refraction of light when it Goes from rarer medium to a Denser medium :

1. When a ray of light goes from a rarer medium to a denser medium , it bends towards the normal ( at the point of incidence ).
2. In this case , the angle of Refraction (r) is smaller than the angle of incidence (i).

Case 2. Refraction of light when it goes from a Denser medium to a Rarer medium.

1. When a ray of light goes from a denser medium to a rarer medium , it bends away from the normal.
2. In this case the angle of refraction (r) is greater than the angle of incidence (i).

Case 3 : Refraction of light when light falling Normally ( Or Perpendicularly) on a Glass Slab :

1. If the incident Ray falls normally to the surface of a glass slab , then there is no bending of the ray of light , and it goes straight.