ultraviolet (UV) /-vī″ələt/ [L, ultra + Fr, violette] , light beyond the range of human vision, at the short end of the spectrum, or that part of the electromagnetic spectrum with wavelengths between about 10 and 400 nm. Equivalently, an ultraviolet photon has an energy between 5 and 500 eV. It occurs naturally in sunlight. It burns and tans the skin and converts precursors in the skin to vitamin D. Ultraviolet lamps are used in the control of infectious airborne bacteria and viruses and in the treatment of psoriasis and other skin conditions. Black light is ultraviolet light used in fluoroscopy. See also angstrom, light, radiation, spectrum.
