Applications of the Parabola

The parabola's headline application is as a reflector/receiver of light or radio waves: cross-sections of car headlights and flashlights are parabolas, formed as a paraboloid of revolution about the axis, with the bulb at the focus (light reflects outward parallel to the axis — Fig. 5.60, proved in §5.7.4). Satellite dishes and field microphones at sporting events work in reverse: incoming waves parallel to the axis are reflected into the focus, intensifying a weak signal (Fig. 5.59). Solar cookers mount a parabolic mirror with the cooking pot at the focal area, so parallel incoming sun rays concentrate there, producing cooking-hot temperatures. …