FTP, name this physical law, which describes the relationship between angle of incidence and angle of refraction.
It can be derived from Fermat's Principle by differentiation. In a special case, it can describe pure reflection, and it also explains the action of a prism on white light. It can be stated as a direct proportion, in which case the constant of proportionality is calculated by dividing the indices of refraction of the two media. FTP, name this physical law, which describes the relationship between angle of incidence and angle of refraction.
It can be derived from Fermat's Principle by differentiation.
Snell's Law