Ultra Violet light or UV rays is an electromagnetic radiation naturally emitted by the sun. It is also radiated by specially created light like the black light. The UV wave length is shorter than the visible light. A UV wavelength determines how long the wavelength of a particular light is. It is measured in nano meters (nm) or electron volts. The UV wavelength is shorter than that of visible light and hence is not visible to the human eye. The color with the highest frequency that humans can see is violet. Since they cannot see the color of the frequency of this light, hence it is known as the ultra violet light.
The instrument named photodiode is used to measure the UV rays. It converts the UV light into a current. Once converted into a current it can be detected and measured. Then the UV light is expressed in volts. The photocathode is also used to measure the UV rays. This instrument produces electronic emissions when the UV rays fall on it. This is used more for detecting the UV lights than to measure it. There is another instrument to determine the UV wavelength, it is known as the UV detector. The near UV length detectors can detect UV rays in the near 200nm to 400nm range. The Vacuum UV detector has an edge over the others. It can block other sources of light and pick up only UV wavelength.
Wavelength of UV
Uv rays have the wavelength in the range 10 nm to 400 nm, and energies from 3eV to 124 eV.
It is not very easy to determine the UV wavelength. This is because each of these machines picks up all light and not just the UV wavelengths. Thus, the results obtained are not accurate and the aim of the apparatus is lost.. It is extremely difficult to separate normal light from the UV light. UV light is both good and bad for the humans. It is a rich source of vitamin D. At the same time can cause severe sunburn and can cause skin cancer.