It will not change path if it is incident along the normal
When light moves from say air into glass, if its angle of incidence is
It depends on what you call the "speed of light".
Being an EM wave, it has two definitions of velocity.
- Phase velocity :
Given as the velocity with which the phase front of the EM wave moves, This is the regular "velocity" we talk about. In space it is
2 . Group velocity:
This is how the "shape" of the wave travels.
By Geek3 - Own work;This mathematical image was created with Mathematica, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=14772688
Now depending on how the medium "reacts" to an incident light wave, this velocity can be decreased, and a beam has actually been stopped.
Interesting video: enter link description here
There you go .. it can be "slowed down", a lot .
Thank you for asking this.