Light in vacuum is incident on the surface of a slab of transparent material. In the vacuum the beam makes an angle of 43.8° wit
h the normal to the surface, while in the slab it makes an angle of 19.3° with the normal. What is the index of refraction of the transparent material?
n1 and n2 represent the indices of refraction for the two media, and θ1 and θ2 are the angles of incidence and refraction that the ray R makes with the normal.