Type of electric discharge lamp consisting of a glass tube filled with a mixture of argon and mercury vapor.
A current of electricity causes the vapor to produce ultraviolet radiation that, in turn, excites a phosphor coating on the inside of the tube, causing it to fluoresce, or reradiate the energy as visible light. Fluorescent lamps are cooler and more efficient than incandescent lamps . They are commonly installed with diffusers as part of a suspended ceiling system. See also fluorescence .