What are ultraviolet rays?
ultraviolet rays are part of an electromagnetic spectrum that includes visible light and other forms of natural radiation such as microwaves and radio waves. Their wavelength is located just over purple light on this spectrum; Therefore their name. Ultraviolet rays are invisible to an uninstalled human eye, but have a wide range of physical effects. These include chemical reactions and positive and negative effects on health on humans and other organisms. The natural ozone layer of the Earth filters a very harmful ultraviolet (UV) radiation.
Many forms of electromagnetic radiation are emitted by the sun and other natural energy sources. The most famous form of this radiation is visible light, but these same sources are emitted by other invisible forms of radiation. The position of this radiation on the electromagnetic spectrum is determined by its wavelength. The light with a long wavelength is reddish color and just behind the red end of the visible spectrum is infrared (IR) Radiaion. OnThe opposite end of the visible spectrum, with a wavelength slightly shorter than blue and purple light, are ultraviolet rays.
ultraviolet rays are divided into several categories, depending on their wavelength and their effects on human health. The ultraviolet radiation closest to the visible light is classified as UVA, UVB and UVC, while closest to X -rays is called extreme ultraviolet (EUV). In humans, the exposure of UVB radiation promotes vitamin D production, the necessary nutrients that helps the immune system. Different forms of UV radiation are used in medical therapy, including the treatment of skin diseases and nutritional shortcomings such as intersections.
Excessive exposure to ultraviolet rays can lead to serious health problems. UV radiation causes repetition because the skin produces melanin, darkened reagent, filters out UV radiation. However, the prolonged exposure may increaseIT risk of health problems such as skin and cataract cancer; This is why manufacturers of sunscreen and sunglasses emphasize their UV filter properties. Various natural substances also filter harmful UV radiation, including glass, earth atmosphere and ozone layers. It is assumed that the reduction of ozone layer can lead to an increase in health problems created by the UVR.
ultraviolet rays have numerous industrial and commercial applications. They can be used to detect chemical signatures, either intentionally placed, for example on waist and money, or those that were formed naturally by substances such as animal waste. Concentrated UV radiation is an effective germicide because many harmful microorganisms cannot tolerate this form of radiation. Scientists use ultraviolet rays for analytical purposes in fields from forensic to astronomy. Inks that fluoresce or glow are used under UV rays to create posters of "black light", clothing and makeup.