Ultraviolet

Ultraviolet radiation is light (i.e., electromagnetic radiation) of a wavelength shorter than that of visible light, but longer than that of soft X-rays. It is often abbreviated to UV. The name means "beyond violet" (from Latin ultra, "beyond"), violet being the color of visible light of shortest wavelength.

UV is usually subdivided into near UV (200-380 nm wavelength) and extreme or vacuum UV (10-200 nm).

Ultraviolet light is the cause of [skin cancer]? such as melanoma - the radiation ionises DNA molecules in skin cells, causing mutations which can result in cancerous growths. As a defence to this the body tan?s when exposed to moderate (depending on [skin type]?) levels of radiation by releasing the brown pigment melanin?. This helps to block the radiation and prevent damage to the vulnerable skin tissues deeper down.

[Fluorescent lamp]?s work by producing UV light by the stimulated emission of low-pressure mercury gas. A phosphorescent? coating on the tubes absorbs the UV and turns it in to visible light.