What Is Refraction of light?
The refraction of light may be defined as the phenomenon of change in direction of light, when it passes from one medium to another.
The cause for refraction of light when it passes through one medium to another is the difference of velocity of light in different media. As you already know that the maximum speed of light is in vacuum or air which is 3 × 108 m/s. but it becomes 25% slow when it travels in water and 35% slow when it travels in glass. Thus when light passes from one medium to another, its speed changes and due to the change in speed of light the refraction of light takes place.