When a ray of light is incident at normal incidence, (at right angles ... to the surface. In refraction calculations, angles are always measured between rays and the normal.

There are different ways to investigate refraction in rectangular blocks. In this required practical activity, it is important to: make, measure and record the angles of incidence accurately using ...

the ratio of the sine of angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media. If c is the speed of light in air and ...