Two light rays, one red and one violet, encounter a glass surface. If the index of refraction of the red light ray = 1.52, the index of refraction of the violet light ray = 1.54, and the angle of incidence = 30 degrees, calculate the angle of refraction of each colour of light ray (from air to glass).

- So considering that these light rays are travelling from air to glass, to find the angle of refraction of the red light ray, do I add its index of refraction and the index of refraction of air, or do I just use one of them (if so, which one)?