Reflection & Refraction

Laws of reflection
1. Angle of incidence equals the angle of reflection.
2. The reflected ray, incident ray and normal all lie on the same plane.

When light goes into glass or another medium it slows down. This causes the light to bend if it enters at an angle that isn't 90°. The relation between the angle of incidence and the angle of reflection is as follows:

The relation between the speed of the incident ray and the speed of the refracted ray too provides a further measure for the refractive index.

Where ci = is the speed of the incident ray
cr = the speed of the refracted ray.

Note the previous two equations refer to light entering glass or another medium causing it to slow down. This results in the light bending towards the normal. However, if the question refers to light leaving glass causing it to speed up then the refactive index is substituted for 1/n and the light bends away from the normal.