A circular pool, having radius R and depth D, is filled to the brim with water. A point source of light is positioned at the center of the pool at a depth of D/2. Now assume that the surface of the bottom of the pool is a perfectly reflecting mirror. Viewed from above the source, how far beneath the surface does the image of the source in the mirror appear to be? A swimmer, whose eyes are at the same depth as the source, sees an image of the source in the top surface of the water that is as bright as the image in the bottom mirror. Explain how this is possible. By what factor has the total amount of light emerging from the top surface of the pool changed by making the bottom surface a mirror? Explain your response. Would this factor change if the sides of the pool were mirrored as well?