Wednesday, July 6, 2011

Ultra-violet light (Matthew)

What is the wavelength?
NUV: 400 nm–300 nm
FUV: 200 nm–122 nm
EUV: 121 nm–10 nm


Does it need a medium?
No


What is it?
Ultraviolet (UV) rays are invisible rays that are part of the energy that comes from the sun. UV rays can burn the eyes, hair, and skin if these parts of the body are not properly protected, or if they undergo too much exposure to the sun. UV light has shorter wavelengths than visible light. Though these waves are invisible to the human eye, some insects, like bumblebees, can see them. UV light can be divided into three types: the near ultraviolet(NUV), the far ultraviolet(FUV), and the extreme ultraviolet(EUV). NUV is the light closest to optical or visible light, EUV, is the ultraviolet light closest to X-rays and FUV lies between the near and extreme ultraviolet regions and is also the least explored.


What are the advantages and disadvantages?
We can study stars and galaxies by studying the UV light they give off, we can even study the Earth. UV rays are also used to treat psoriasis; the rays slow the growth of skin cells, preventing the outbreak of the itchy patches for which psoriasis is known. In spite of all their positive uses, UV rays remain very harmful for anyone who spends a large amount of time in the sun without proper protection. The most common effect of exposure to UV rays is sunburn, which may eventually lead to skin cancer.


Sources: http://science.hq.nasa.gov/kids/imagers/ems/uv.html
http://www.wisegeek.com/what-are-uv-rays.htm

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