instruction: How can UV light be used?
response: UV light is electromagnetic radiation.  It has a wavelength that is shorter than regular visible light.  UV light can be used in water purification to kill viruses and bacteria in city water.  Continuous flow UV lights can kill virus and bacteria up to 99.999%.  This is very helpful because it keeps people from ingesting virus and bacteria in their water source.  UV light has other applications such as tanning beds.  UV light can also be used in disinfecting services too.