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Showing posts from September 23, 2014
INFRARED (IR) :- This  light is electromagnetic radiations with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nanometer (nm) to 1 mm. Wavelengths of these ra ys corresponds to a frequency range of approximately 430 THZ down to 300 GHz, and includes most of the thermal radiation emitted by objects near room temperature. Infrared light is emitted or absorbed by molecules when they change their rational-vibrations movements. It was first discovered in 1800 by astronomer William Herschel. Slightly more than half of the energy from the Sun arrives on Earth in the form of infrared radiation. The balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate. History of Infrared:- The discovery of this radiation is ascribed to William Herschel, the astronomer, in the early 19th century. He published his results in 1800 before the Royal Society of London. He used a prism to refract li