1) The speed of light in a specific medium is 0.8 c where c is the speed of light in vacuum. The refractive index of this medium is: 2) A light ray is incident upon a plane interface between two materials. The ray makes an incident angle with the normal to the surface of 36 degrees in a material with index of refraction 1.25. If the second material has an index of refraction 1.87, what is the refracted angle in degrees in that material? 3) What is the critical angle for a light ray incident on an interface between two media with indexes of refraction n = 1.6 and n = 1.2?