Question

what is the main cause of refraction?​

Answer 1

Light refracts whenever it travels at an angle into a substance with a different refractive index (optical density). This change of direction is caused by a change in speed. For example, when light travels from air into water, it slows down, causing it to continue to travel at a different angle or direction.

Answer 2

Answer:

Light travelling from one medium to another.

Explanation:

when light travels from one medium to another, it changes direction (light bends). this is called refraction.