Composition

Composition

The spectrum o striking the  is 100 to 10⁶  This can be divided into five regions in increasing order of

The of the's solar radiation is close to that of a y with a temperature of about 5,80 About half that lies in the short-wave part of the  and the other half mostly in the near- part. Some also lies in the  part of the spectrum When ultraviolet radiation is not absorbed by the atmosphere or other protective coating, it can cause damage to the skin known as or trigger an adaptive change in human

• Ultraviolet C or (UVC) range, which spans a range of 100 to 280 nm. The term ultraviolet refers to the fact that the radiation is at higher frequency than violet light (and, hence also invisible to the human eye). Owing to absorption by the atmosphere very little reaches the Earth's surfaceThis spectrum of radiation has  properties, and is used in 
• Ultraviolet B or (UVB) range spans 280 to 315 nm. It is also greatly absorbed by the atmosphere, and along with UVC is responsible for the eading to the production of the 
• Ultraviolet A or (UVA) spans 315 to 400 nm. It has been traditionally held as less damaging to the , and hence used inand  for
• Visible range orspans 380 to 780 nm. As the name suggests, it is this range that is visible to the naked human eye.