Ultraviolet light (UV) is a part of normal sunlight.
But it cannot be seen with naked eyes.
UV is an electromagnetic radiation with the wave lengths in the range of 10 to 400nm.
It is present in sunlight and can also be produced by electric arc lamps.
It has higher frequency and shorter wave length than visible light.
This means this radiation has greater energy than normal visible light.
It can cause chemical reactions and make other substances to florescence.
Hence UV light is a bit harsh on skin and eyes when directly exposed.
The ozone layer on the surface of the earth prevent them from reaching the earth to a large extent. This saves us from the harmful effect of UV light from sun.
But Ultraviolet light has been found to have many application to man.
Ultraviolet Light Uses
1. Analytical research
2. Medicine as photo-therapy
3. Vitamin D formation and strengthen bones
4. Sterilization of substances
5. Air purification
6. To trap insects
Analytical research: UV light is widely used in analysis of substances. The spectrophotometers employ UV light to detect and measure the concentration of a given sample in liquid form. These spectrometers are used individually or in combination with other techniques like chromatography.
Besides these certain plant extracts and chemicals are stained or have inherent dyes which make them detectable when put in UV environment. For this, the sample is put in a UV chamber and observed.
Thus UV light helps in analysis and research of many chemical and biological substances.
In Medicine: For certain skin diseases like psoriasis and other skin conditions, the prolonged exposure to UV light is a better therapy. This exposure to UV light is called as photo-therapy. Here the patient will be relieved of the problems even without use of medicines but just by exposure to the light.
Even new born babies can have jaundice due to break down of hemoglobin. Then doctors treat them by photo therapy by using bright light or UV light. When the skin of baby is exposed to light for long periods, the bilirubin in the skin breaks down to water soluble form and gets out of the body through urine.
Vitamin D formation: Vitamin D is a type of vitamin which need not be consumed from food. It is synthesized in the skin due to irradiation of ergosterol by sunlight. UV light in the sun is key for formation of Vitamin D. Thus the formed Vitamin-D helps storage of calcium in the bones and there by strengthen them.
Sterilization of substances: UV radiation is a type of dry heat method of sterilization. For details go through sterilization methods. UV when falls on the cells, it can destroy the DNA and other essential molecules due to its energy. Hence when the substances are exposed to UV light at predefined wave length and time, there will be effective sterilization.
This method of sterilization can be used for bulk process and also for keeping a specific room or chamber sterile.
Air purification: Air is composed of organic debris, carbon monoxide and even some microbes.
This air can be purified by UV radiation.
UV radiation has enough strength to kill the microbes and also destroy the organic debris and carbon monoxide.
So employing a UV light source can help purify the air around.
To trap insects: Insect trap instruments have UV light emitters.
Thus these instrument can keep insects away from us.