Are refracted waves faster or slower than incident waves?

Refracted waves can be faster or slower as compared to the incident waves, depending on the optical density of the medium.

Refraction defines the bending of a light ray when it moves from one medium to another. Each medium has a certain optical density and this determines the speed of light rays through it. Light rays travel slowly in a denser medium, while they have higher speeds in a rarer medium. Thus, the transition from...

Refracted waves can be faster or slower as compared to the incident waves, depending on the optical density of the medium.

Refraction defines the bending of a light ray when it moves from one medium to another. Each medium has a certain optical density and this determines the speed of light rays through it. Light rays travel slowly in a denser medium, while they have higher speeds in a rarer medium. Thus, the transition from one medium to another causes light rays to bend. Lights rays will either bend towards the normal (drawn to the surface) or away from it. When light rays move from a fast medium to a slow medium, they bend towards the normal. In comparison, when light rays move from a slow medium to a fast medium, they bend away from the normal. 

We can use Snell's law to determine the speed of the light ray in any medium. The law is given as:

(sin i)/(sin r) = v1/v2

where, i and r are the angles made by incident and refracted rays (with the normal) and v1 and v2 are the velocities of light rays in medium 1 and 2.