| intermediate rays | Those between ultraviolet and X-ray's. Synonym: W rays. (05 Mar 2000) |
|---|---|
| ultrasonic rays | See: ultrasonic. (05 Mar 2000) |
| ultraviolet rays | That portion of the electromagnetic spectrum immediately below the visible range and extending into the X-ray frequencies. The longer wavelengths (near-uv or biotic or vital rays) are necessary for the endogenous synthesis of vitamin d and are also called antirachitic rays; the shorter, ionizing wavelengths (far-uv or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants. (12 Dec 1998) |