Properties of Ultraviolet Waves
- Wavelength(m)-1 x 10-8 - 4 x 10-7
- Frequency (Hz)-7.5 x 1014 - 3 x 1016
- HAve shorter wavelengths than visible light
- The are invisible to the human eye but can be seen by some insects and animals; bumblebees, birds, reptiles
- The Ultraviolet part of the Em spectrum has been divided into three regions: Near ultraviolet, Far Ultraviolet, Extreme ultraviolet
- the three regions are distinguished by how energetic the ultraviolet radiation is, and by the Wavelength of the ultraviolet light which is related to energy
- The Near Ultraviolet, abbreviated (NUV), is the light closest to optical or visible light
- The far ultraviolet, abbreviated FUV, lies between the near and extreme ultraviolet regions. It is the least explored of the three regions.
- The extreme ultraviolet, abbreviated (EUV), is the ultraviolet light closest to X-rays, and is the most energetic of the three types.
- Banks use UV light to check for counterfeit money
- Uv light can be blocked by thick clouds
- Uv light can be used to disinfect surfaces.
- Hospitals use them to disinfect rooms
- Labs in schools use them to disinfect the goggles.
- Our Sun puts off light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns.
- Tanning beds use UV light to recreate the suns waves
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- Johann Ritter discovered Ultraviolet light in 1801.
- he was experimenting with silver chloride, a chemical which turned black when exposed to sunlight.
- Ritter decided to measure the rate at which silver chloride reacted when exposed to the different colors of light. To do this, he directed sunlight through a glass prism to create a spectrum.
- Ritter noticed that the silver chloride showed little change in the red part of the spectrum, but increasingly darkened toward the violet end of the spectrum.
- This proved that exposure to blue light did cause silver chloride to turn black much more efficiently than exposure to red light.
- Johann Ritter then decided to place silver chloride in the area just beyond the violet end of the spectrum, in a region where no sunlight was visible.
- he saw that the silver chloride displayed an intense reaction well beyond the violet end of the spectrum, where no visible light could be seen. This showed for the first time that an invisible form of light existed beyond the violet end of the spectrum.
- This new type of light, which Ritter called Chemical Rays, later became known as ultraviolet light or ultraviolet radiation.