Infrared RadiationInfrared radiation, infrared rays and electromagnetic radiation occupy the spectral domain between the red end of visible light spectrum and short-wave radio-frequency emission. The infrared spectrum range is provisionally classified into near, intermediate and far-infrared radiation. V. Herschel, a genius English scientist, discovered infrared radiation in 1800. Then it was proved that infrared radiation is in line with optical laws, therefore, its nature is similar to visible light. Similar to visible and ultraviolet radiation spectra, infrared radiation spectrum may either be made up of discrete lines or be continuous. This depends on infrared radiation source. Generally, optical properties (transparency, reflection factor, and refraction factor) within the infrared domain substantially differs from properties occurring within visible and ultraviolet domains. Many substances transparent within the visible domain turn out to be non-transparent in the infrared domain and vice versa.The Earth atmosphere attenuates infrared radiation as it disperses and is absorbed. Nitrogen and oxygen contained in air do not absorb infrared radiation. Though they attenuate radiation due to its dispersal. However, it disperses less than visible light. Water vapors, carbon-dioxide, ozone and other air impurities selectively absorb infrared radiation. Water vapors whose absorption bands lie within almost the whole infrared spectrum domain are the most intensive infrared radiation absorbers; while it is carbon dioxide that intensively absorbs radiation within the intermediate infrared region. Suspended solids contained in the atmosphere i.e. smoke, dust, dispersed water drops (mist, fog) additionally attenuate infrared radiation as it disperses much intensively. Note that the dispersal value depends on the ratio between the sized of such suspended solids and radiation wave length. The Sun is a powerful infrared radiation source as about 50% of radiation emitted by Sun lies within the infrared domain.Some laser oscillators also emit radiation within the infrared domain; for instance, the wave length of neodymium-doped glass laser radiation is 1.06 micrometer; helium/neon laser emits radiation with the wave length of 1.15 and 3.39; and carbon dioxide laser yields the wave length of 10.6 micrometer, while semiconductor laser provides the wave length of 5 micrometer. Infrared radiation finds a wide utility in scientific research, electronic engineering, for instance, for infrared diodes and photodiodes, heavy engineering. It is also extremely useful for military industry - for radar sets, range finders, night vision equipment, land-based and space communication equipment.One of the most important infrared radiation utilities is its favorable influence on a human body. When radiantly heated, a human body emits most of excess heat to cooler air through convection. Such kind of heat exchange makes people feel fresh and is good for human health!
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The Light Spectrumby dizzo9559,655 views
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dynamicaster 9 months ago