19.07.2016
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Definition of Electromagnetic spectrumFor convenience in talking about electromagnetic radiation, we classify photons of different energies into different spectral regions. Add important lessons to your Custom Course, track your progress, and achieve your study goals faster.
Definition of Ultraviolet LightUltraviolet (UV) light is a type of electromagnetic radiation that is all around us even though our eyes can't detect it.
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We are happy to resend any lost item (usually after 14 working days) but we ask that you contact your local sorting office first to check it's not been left there - 95% of our missing parcels are left in sorting offices! We take great care in delivering your product in perfect condition, if by any chance your product is damaged, or develops a fault we will do our up most to solve your problem.
Most purchases from business sellers are protected by the Consumer Contract Regulations 2013 which give you the right to cancel the purchase within 14 days after the day you receive the item. By clicking Confirm bid, you are committing to buy this item from the seller if you are the winning bidder and have read and agree to the Global Shipping Programme terms and conditions - opens in a new window or tab. By clicking 1 Click Bid, you are agreeing to buy this item from the seller if you're the winning bidder. The photons in all of these regions have the same electromagnetic nature, but because of their very different energies they interact with matter very differently.
In this lesson, we'll learn where UV light comes from, how it affects living things, and how it is used in many other applications.


Our bodies use it to make vitamin D, but too much exposure can cause painful burns and even cancer. Delivery times may vary, especially during peak periods and will depend on when your payment clears - opens in a new window or tab. If the item comes direct from a manufacturer, it may be delivered in non-retail packaging, such as a plain or unprinted box or plastic bag. We assure you that this will only be used by the courier or the postal services or by a member of our customer service team, in the unlikely event that there is a problem with your order. The product must be returned to us in the original and un-used condition and in it's original box and packaging.
A UK based company growing rapidly to become one of the foremost suppliers of computer technologies and consumer electronics. We offer our customers maximum satisfaction by maintaining high quality standards at nominal rates. Find out more about your rights as a buyer - opens in a new window or tab and exceptions - opens in a new window or tab. By clicking Confirm bid you commit to buy this item from the seller if you are the winning bidder. Import charges previously quoted are subject to change if you increase you maximum bid amount. For example, the human eye can only detect radiation that is in the visible region of the spectrum (hence the name). This is used in crime scene analysis as well as to check for sanitation of bathrooms and other public spaces where these fluids may be present but invisible to the naked eye.
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These photons are both transmitted by the lens of the human eye and absorbed by the photoreceptors in the retina. UV light is used to identify biological materials, like blood, at crime scenes and in places where sanitation is important.
There is no fundamental difference in the nature of electromagnetic radiation of 350 nm versus 400 nm, other than our eyes can sense the 400-nm photons directly. Because it can kill viruses and bacteria, it is also used to sterilize medical and biological research facilities and to sanitize much of our food and water. Sterilization UV light damages DNA, and therefore, has the ability to kill bacteria and viruses. Electromagnetic WavesAs previously mentioned, ultraviolet light is one type of electromagnetic wave. It's often used to sanitize workspaces in medical and biological research facilities and to sterilize water and other foods that would be damaged by heat sterilization. Some of the boundaries between spectral regions are not well-defined as between ultraviolet and visible radiation. Electromagnetic waves are different than waves on a string or waves that you see in water because they don't need anything to travel through; they are waves of pure energy and because of this, they can travel through empty space. Lesson SummaryUV light is a type of radiation that is all around us even though our eyes can't detect it since it has a frequency higher than that of visible light. Visible SpectrumThe visible region of the electromagnetic spectrum consists of photons with wavelengths from approximately 400 to 700 nm.
The short wavelength cutoff is due to absorption by the lens of the eye and the long wavelength cutoff is due to the decrease in sensitivity of the photoreceptors in the retina for longer wavelengths.


All visible colors of light, as well as microwaves, X-rays, and radio waves, are also electromagnetic waves.
The only difference between these types of electromagnetic waves is their frequency and wavelength. Electromagnetic SpectrumThe following table lists the names of different spectral regions, the range of frequencies and wavelengths in those regions, and the type of transition that can occur when a photon in these spectral ranges interacts with matter.
Ultraviolet waves, with wavelengths from 40-400 nanometers (nm), are those that fall between visible light and X rays on the electromagnetic spectrum. UV light can be broken down into five different types based on their wavelengths, including vacuum UV (40-190 nm), far UV (190-220 nm), UVC (220-290 nm), UVB (290-320 nm), and UVA (320-400 nm).
Because ultraviolet light has a frequency higher than that of visible light, it carries more energy and has the ability to penetrate our skin. The first three types are absorbed into the ozone layer of the Earth's atmosphere, while UVB and UVA make their way through. Prolonged exposure to ultraviolet light can cause sunburns and DNA damage, which can contribute to the development of skin cancer. It's actually UVB radiation that leads to DNA damage in humans (in addition to skin cancer, cataracts, and those painful sunburns you've probably had at one point or another). Artificial sources include tanning booths, black lights, germicidal lamps, mercury vapor lamps, halogen lights, high-intensity discharge lamps, fluorescent and incandescent sources, and some types of lasers. The UV spectrum is divided into vacuum UV (40-190 nm), far UV (190-220 nm), UVC (220-290 nm), UVB (290-320 nm), and UVA (320-400 nm). UV dyes are used in fabric and paper to make them appear brighter, and UV light will also cause biological substances, like blood and urine, to appear fluorescent. The highest energy forms of UV light (Vacuum UV, Far UV, and UVC) are almost completely absorbed by the Earth's atmosphere in the ozone layer.
Since UV light damages DNA, it quickly kills DNA and viruses and is commonly used to sterilize food and water, as well as medical and biological research facilities.
UVB is typically the most destructive form of UV radiation because it has enough energy to damage cellular DNA yet not enough to be completely absorbed by the atmosphere.
Humans need to be exposed to some UVB rays so that we can produce vitamin D, a critical nutrient for bone production and repair.
However, overexposure to UV light can cause sunburn, cataracts, and eventually lead to the development of skin cancer. UVA exposure causing tanning of the skin initially, followed by sunburn after prolonged exposure. Ozone in the atmosphere absorbs very little UVA radiation, and it is present even on cloudy days. However, just like UVB, overexposure to UVA has been associated with toughening and wrinkling of the skin, suppression of the immune system, cataract formation, and skin cancer.
Some Applications of UV LightHere are some different ways UV light is used by human beings.
Fluorescent dyes When UV light shines on certain dyes, they emit a light in the visible spectrum called fluorescence. Many fabrics and papers contain UV sensitive dyes that emit visible light when exposed to UV light. To prevent counterfeiting, most paper currency is printed with a watermark or strip of UV-sensitive dye that can only be seen using a UV black light.



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Comments Uv light definition biology

  1. QIZIL_UREY
    For plastic repair but can be used.
  2. SS
    Might come with slightly different instructions for how able to remember??this.