Ultraviolet 2 topics · 2 sources ScienceAstronomyElectromagnetic radiation at wavelengths shorter than 400 nm.NASA — NASA Helioviewer.org Visual Glossary retrieved 2014-05-26 Cite ScienceEnergyElectromagnetic radiation in the wavelength range of 4 to 400 nanometers.US DOE Office of Energy Efficiency & Renewable Energy — Glossary of Energy-Related Terms retrieved 2014-05-26 Cite