REFRACTION

Refraction Of  Light

Light travels at different speeds in different media. When light passes from one transparent medium into another, it may either  slow down or travel faster. This change in the speed of light moving through different  media causes the light to bend when it hits the surface at an angle to the normal. Refraction of light is the change in direction of light when it moves from one transparent medium to another due to the difference in the speed of light in the two different media.

If light increases its speed when passing from one medium to another, it will bend away from the normal. If  the speed of light decreases when travelling from one medium to another, it will bend towards the normal.

Light travels more slowly  in glass than in air. When light moves from the air into glass  at an angle, one side of the light beam slows down as compared to the other. This change in speed makes the light bend.