Lying outside the visible spectrum at its blue-violet end; -- said of light more refrangible (i. e. having a shorter wavelength) than the extreme violet rays of the visible spectrum. Electromagnetic radiation with wavelengths shorter than those of ultrviolet light are not usually considered as light waves, but are classified differently. The ultraviolet region of the electromagnetic spectrum is generally considered as comprising those electromagnetic emissions with wavelengths lying between those of visible light and those of X-rays, i. e. between 4000 Angstroms and 100 Angstroms.
A region of the electromagnetic spectrum that is of higher energy and shorter wavelength than visible light. Typical wavelengths of ultraviolet radiation range from 375 nm to 12.5 nm (12.5 x 10-9 m).
electromagnetic rays beyond the violet end of the visible spectrum. The range of invisible radiation wavelengths from around 4 nanometers to 380 nanometers. Often called UV radiation and comes naturally from the sun. Divided into 3 categories based on wavelength.