The phenomenon in which when a ray of light travels from one medium to another, bends at the boundary between the two medium

Ray of light bends as light travels from one medium to another.

If a wave is going from one medium to another, then

If a wave is going from one medium to another, then

When a ray of light from air enters a denser medium, it :

When a ray of light travels obliquely from a rarer medium to a denser medium, it bends away from the normal.

When a ray of light travels from optically denser medium to optically rarer medium, it always bends towards the normal.

What is the cause of refraction of light when it passes from one medium to another ?

Which colour of light travels fastest in any medium except air ?

The phenomenon due to which a ray of light _____ from its path while travelling from one optical medium to another optical medium is called refraction.