2.4 A ray of light enters a transparent cube made from two triangular prisms of identical dimensions but different indices of refraction, as shown in the diagram. The ray enters one side of the cube at an angle, and exits the cube perpendicular to the other side of the cube, at the midway point between the cube's top and bottom. (Note: The ray remains parallel to the face of the cube parallel to the plane of the page it has no component of propagation into or out of the page.)