The brief account of acquainted phenomena given over surveyed electromagnetic radiation from low frequencies the ν (radio waves) come exceedingly high worths of ν (gamma rays). Going indigenous the ν worths of radio tide to those the visible light is prefer comparing the thickness the this web page with the street of planet from the Sun, which represents boost by a element of a million billion. Similarly, going indigenous the ν values of visible irradiate to the an extremely much bigger ones of gamma rays represents an additional increase in frequency by a element of a million billion. This extremely big range of ν values, dubbed the electromagnetic spectrum, is displayed in figure 1, together with the typical names offered for its assorted parts, or regions.
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Figure 2: Radiation fields in i m sorry vectors E vector and B vector space perpendicular to each other and to the direction of propagation (see text).
Generation of electromagnetic radiation
Electromagnetic radiation is developed whenever a charged particle, such together an electron, changes its velocity—i.e., whenever that is accelerated or decelerated. The power of the electromagnetic radiation thus produced originates from the charged particle and also is thus lost by it. A common example the this phenomenon is the oscillating charge or current in a radio antenna. The antenna of a radio transmitter is part of an electrical resonance circuit in i beg your pardon the charge is made to oscillate in ~ a wanted frequency. One electromagnetic tide so generated can be got by a similar antenna connected to one oscillating electrical circuit in the tuner the is tuned to that very same frequency. The electromagnetic wave in turn produces an oscillating motion of fee in the receiving antenna. In general, one deserve to say that any type of system i m sorry emits electromagnetic radiation of a provided frequency can absorb radiation the the very same frequency.
Such human-made transmitters and receivers become smaller through decreasing wavelength of the electromagnetic wave and also prove impractical in the millimetre range. At even much shorter wavelengths under to the wavelengths of X-rays, which room one million time smaller, the oscillating charges to happen from relocating charges in molecules and atoms.
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One might classify the generation of electromagnetic radiation into two categories: (1) equipment or processes that develop radiation spanning a broad continuous spectrum the frequencies and also (2) those that emit (and absorb) radiation the discrete frequencies that room characteristic of details systems. The sun with its constant spectrum is an instance of the first, when a radio transmitter tuned to one frequency illustration the 2nd category.