1. The problem statement, all variables and given/known data Define refractive index in terms of changes in the velocity of a wave in passing from one medium to another. 2. Relevant equations 3. The attempt at a solution Would I be right in saying that in terms of the question above, refractive index is the constant found between the velocity of a wave in one medium, divided by the velocity of that same wave in another medium that it is traveling into. I just wanted to make sure as this is a syllabus question for my exams... thanks for any help.