Radiation is the emission (sending out) of energy from any source. There are many types of radiation.
Ultraviolet (UV) radiation is a form of electromagnetic radiation. The main source of UV radiation (rays) is the sun, although it can also come from man-made sources such as tanning beds and welding torches.
Radiation exists across a spectrum from very high-energy (high-frequency) radiation – like x-rays and gamma rays – to very low-energy (low-frequency) radiation – like radio waves. UV rays have more energy than visible light, but not as much as x-rays.Higher energy UV rays often have enough energy to remove an electron from (ionize) an atom or molecule, making them a form of ionizing radiation. Ionizing radiation can damage DNA in the cells in our body, which in turn may lead to cancer. But because UV rays don’t have enough energy to penetrate deeply into the body, their main effect is on the skin.
Scientists often divide UV radiation into 3 wavelength ranges: