Ultra-Violet Radiation

Ultra-violet radiation is the radiation beyond the violet end of the visible spectrum.(wavelengths range from 10-8 to 10-7 m)
The main source of ultra-violet radiation is sunlight and it is this radiation which gives rise to suntans.
Ultra-violet radiation from the sun also stimulates our body to produce vitamin D, which we need for healthy bones.
However overexposure to ultra-violet radiation can cause skin-cancer and damage to the retina.
Ultra violet radiation also kills bacteria and viruses. Thus it is used to sterilize hospital operating rooms and surgical instruments.
Low intensity ultra-violet lamps are sometimes placed above grocery meat counters to reduce spoilage.