Click and drag
to change
the values of applet parameters.Light coming from an approximate point source (light bulb) will propagate through space in all directions, which means that the brightness of the light will quickly decrease as you move away from the source. Sometimes we need to keep light in a beam so we can shine it on a distant object (flashlight). A paraboilc reflector will do just that, it will reflect light from a point source in one direction, or it will focus parallel light into a point source. The shape of a parabolic reflector is derived from a simple equation. Y=X2