Answer
The speed of light in the material is v = c/n.
Work Step by Step
As seen in Figure 23-24, a light ray entering the rectangular object exits the other side on a parallel path that is displaced from it. The refraction angle inside the object is found using geometry, because we can measure the displacement and the thickness of the object. Finally, with this angle of refraction and the angle of incidence, we solve for the index of refraction using Snell’s law.