What law explains how the change in direction of the light ray depends on how the speed of light changes, which in turn is related to the indices of refraction of the media involved?

The four Science Regents exams (Earth Science, Living Environment, Chemistry, and Physics) also include separately-scheduled lab practicals.
In New York, students have the opportunity to take Regents Exams in grades 9-12 and, when appropriate, in grade eight.