, Refraction takes place because, when light enters a new medium (with different density) it bends, since it travels with different speeds in different mediums.
, There have to be two optically different mediums, since it occurs when ray of light travels from one medium to another, optically different one.
, Light travels slower through the water than through the air:
a. Refraction is the bending of light when it enters a different medium from another medium. This is because light travels at different speeds in different mediums.