The draft ISO standard on determining solar irradiances (ISO-DIS-21348) describes the ranges listed in the table below.
Discovery of ultravioletUltraviolet light was discovered in 1801 by the German physicist Johann Wilhelm Ritter (1776–1810). He made the discovery while working with silver chloride, which decomposes in the presence of light, especially ultraviolet light. (Ritter also worked in electrochemsistry and in 1802 made the first dry cell.)
Health-related effects of UVThe ultraviolet light (mainly UVA) that reaches the Earth's surface causes tanning and the production of vitamin D in the skin. It can also have harmful effects, such as skin cancer. This form of light is generated by tanning beds and booths to produce a suntan. Tanning beds are designed to emit only UVA rays; however, in practise they also emit some UVB, which is more likely to causing burning and skin cancer.
Ultraviolet light is also produced by welding torches, carbon arc lamps, and some lasers. Special precautions, such as the use of goggles, should always be taken when using such equipment.
UV light is sometimes used in phototherapy to treat skin disorders such as eczema, psoriasis, and jaundice in newborn babies.
Related category WAVES AND WAVE PHENOMENA
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