what causes bending of light during refraction?
Hi Abhijeet!
Speed of light of ray increases when it goes to rarer medium from denser medium. It can be understood by knowledge of propagation of light.
Light is an electromagnetic wave, and electromagnetic wave does not require a medium to propagate. Electromagnetic waves have two components: the electric component and the magnetic component. These two components are perpendicular to each other and are in phase, therefore the point at which they meet they push off one another and propel itself forward. Therefore EM waves do not require a medium.
Now, when EM wave enter a medium, it faces resistance by the electrical and magnetic properties of the medium, due to which its speed decresses. As a result of change in speed and other resistive factors, ray of light changes its original path and bends toward normal.
Hope it is clear to you!
Good luck!!