Ultraviolet
For other uses, see Ultraviolet (disambiguation) . "UV" redirects here. For other uses, see UV (disambiguation) . Portable ultraviolet lamp UV radiation is also produced by electric arcs . Arc welders must wear eye protection and cover their skin to prevent photokeratitis and serious sunburn . Ultraviolet ( UV ) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays . UV radiation is present in sunlight constituting about 10% of the total light output of the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps , tanning lamps , and black lights . Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms , i...