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Infrared radiation

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noun, plural: infrared radiations

A form of electromagnetic radiation emitting infrared rays


The electromagnetic radiation is the radiation released in the form of electromagnetic waves. The distance between successive crests is called the wavelength. The shorter the wavelength, the greater is the amount of energy. There are many forms of electromagnetic radiation. One of them is infrared radiation, which is a type of electromagnetic radiation with wavelengths between 700 nanometres (frequency 430 THz) and 1,000,000 nanometres (or 1 millimetre) (300 GHz). This is more commonly known as heat energy. Infrared radiation was discovered by William Herschel, an astronomer when he discovered an invisible radiation in year 1800. It was applied in medical, scientific (e.g. sensor-equipped telescopes), and industrial fields (e.g. night-vision devices). In medical field, for instance, infrared thermal-imaging cameras are used to monitor heat loss in insulated systems, skin blood flow, etc. The infrared spectrum may be divided into near infrared (or short-wave, i.e. about 0.75 to 3.0 μm) and far infrared (or long-wave, i.e. about 3.0–1000 μm).1

Infrared radiation is not visible to human eye. However, it can be felt as heat especially when the intensity is sufficient. It can penetrate body tissues to about 1 cm deep. It is used therapeutically by promoting muscle relaxation, improved body circulation, and inflammatory process.1

Abbreviation / Acronym:

  • IR

See also:

1 infrared. (n.d.) Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. (2003). Retrieved from [[1]]