How are ultraviolet rays helpful????

Question

How are ultraviolet rays helpful????

Answer 1

UV rays have many industrial applications.

Ultra Violet germicidal Irradiation (UVGI) in medical, sanitary applications for air and water purification.

UV rays are used to assess genuineness of currency notes and to weed out fakes.

Answer 2

http://en.wikipedia.org/wiki/Ultraviolet...

Hope it'll be useful!

Answer 3

Assuming that you mean "how are they helpful on Earth's surface, to us"; UV radiation is the main cause of the production of vitamin D in human skin and probably in the biosphere in general. The UV radiation alters the chemistry of animal and plant steroid chemicals in such as way as to form precursors of vitamin D.

Also, UV rays kill bacteria, which can be useful in certain situations.

Some plants have patterns in their flowers that are only visible in the near ultraviolet - which some insects and birds can see - thus making it easier for those animals to find the plant. This gives them nectar and gets the plant pollinated.

UV radiation is often used to cause fluorescence - which among other things can help detect forged banknotes, and make white cloth look whiter (literally whiter than white, because the cloth has been treated and/or washed with fluorescent chemicals and therefore emits slightly more light than is falling on it).

Answer 4

UV rays can clear the dust,gas particles between stars in order to see the planets clearly.

Answer 5

For blacklight paint and phosphorescent ink.  This is especially useful for neon posters as well as forensics.  And if you hold up a $5 bill to a black light, you see a special water mark in it, which is very hard to counterfeit.

Answer 6

They're pretty good for sterilizing food.

Handy if you want a tan.