If the angle of incidence becomes large enough that the angle of refraction equals 90∘, the light ray will not enter the new medium with the smaller angle of refraction. When two swimmers are under wa...If the angle of incidence becomes large enough that the angle of refraction equals 90∘, the light ray will not enter the new medium with the smaller angle of refraction. When two swimmers are under water in a swimming pool, it is possible for the interface between the water and the air to act as a mirror, allowing the swimmers to see images of each other if they look up at the underside of the surface.
