The Electromagnetic Spectrum refers to the full range of all possible Electromagnetic Field energy frequencies. n. The entire range of electromagnetic radiation, which includes, in order of increasing frequency and decreasing wavelength, radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays. Although all electromagnetic waves travel at the speed of light in a vacuum, they do so at a wide range of frequencies, wavelengths, and photon energies. The ancient Greeks recognized that light traveled in straight lines and studied some of its properties, including reflection and refraction. In most of the frequency bands above, a technique called spectroscopy can be used to physically separate waves of different frequencies, producing a spectrum showing the constituent frequencies. Colored Slides. Spectroscopy: Interaction of light and matter. These behaved similarly to visible violet light rays, but were beyond them in the spectrum. The infrared part of the electromagnetic spectrum covers the range from roughly 300 GHz to 400 THz (1 mm – 750 nm). Microwaves are the main wavelengths used in radar, and are used for satellite communication, and wireless networking technologies such as Wi-Fi. There are no precise accepted boundaries between any of these contiguous portions, so the ranges tend to overlap. It ranges from extremely long wavelengths (extremely low frequency exposures such as those from power lines) to extremely short wavelengths (x-rays and gamma rays) and includes both non-ionizing and ionizing radiation. The brief account of familiar phenomena given above surveyed electromagnetic radiation from low frequencies of ν (radio waves) to exceedingly... Radio waves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays are all types of electromagnetic radiation. The higher energy (shortest wavelength) ranges of UV (called "vacuum UV") are absorbed by nitrogen and, at longer wavelengths, by simple diatomic oxygen in the air. [11], The types of electromagnetic radiation are broadly classified into the following classes (regions, bands or types):[5], This classification goes in the increasing order of wavelength, which is characteristic of the type of radiation.[5]. The electromagnetic spectrum Heinrich Hertz’s production in 1888 of what are now called radio waves, his verification that these waves travel at the same speed as visible light, and his measurements of their reflection, refraction, diffraction, and polarization properties were a convincing demonstration of the existence of Maxwell’s waves. Entire range of frequencies of electromagnetic radiation, Digital dividend after digital television transition, "The Electromagnetic Spectrum, The Physics Hypertextbook", "Introduction to the Electromagnetic Spectrum and Spectroscopy", "CODATA Recommended Values of the Fundamental Physical Constants: 2006", "Essential Radio Astronomy: Pulsar Properties", Corrections to muonic X-rays and a possible proton halo, "Advanced weapon systems using lethal Short-pulse terahertz radiation from high-intensity-laser-produced plasmas", "Reference Solar Spectral Irradiance: Air Mass 1.5", Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose, Uses of Electromagnetic Waves | gcse-revision, physics, waves, uses-electromagnetic-waves | Revision World, Australian Radiofrequency Spectrum Allocations Chart, Poster "Electromagnetic Radiation Spectrum", Electromagnetic Spectrum Strategy: A Call to Action, Linguistic relativity and the color naming debate, International Commission on Illumination (CIE), https://en.wikipedia.org/w/index.php?title=Electromagnetic_spectrum&oldid=996084275, Short description is different from Wikidata, Articles with unsourced statements from November 2015, Creative Commons Attribution-ShareAlike License, Collective oscillation of charge carriers in bulk material (, Molecular vibration, plasma oscillation (in metals only), Molecular electron excitation (including pigment molecules found in the human retina), plasma oscillations (in metals only), Excitation of molecular and atomic valence electrons, including ejection of the electrons (. Unlike higher frequency waves such as infrared and light which are absorbed mainly at surfaces, microwaves can penetrate into materials and deposit their energy below the surface. The electromagnetic spectrum is a continuous range of wavelengths. The behavior of EM radiation depends on its wavelength. [7] He was studying the temperature of different colors by moving a thermometer through light split by a prism. It can be divided into three parts:[5]. Wavelength is inversely proportional to the wave frequency,[5] so gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths on the opposite end of the spectrum can be as long as the universe. This range is known as the electromagnetic spectrum. Many astronomical gamma ray sources (such as gamma ray bursts) are known to be too energetic (in both intensity and wavelength) to be of nuclear origin. Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. X-rays are also emitted by stellar corona and are strongly emitted by some types of nebulae. The electromagnetic spectrum comprises the span of all electromagnetic radiation and consists of many subranges, commonly referred to as portions, such as visible light or ultraviolet radiation. [19] This is an amount sufficient to block almost all astronomical X-rays (and also astronomical gamma rays—see below). Visible light is the portion of the electromagnetic spectrum that is visible to the human … EM radiation spans an enormous range of wavelengths and frequencies. Electromagnetic radiation with a wavelength between 380 nm and 760 nm (400–790 terahertz) is detected by the human eye and perceived as visible light. Photon energy is directly proportional to the wave frequency, so gamma ray photons have the highest energy (around a billion electron volts), while radio wave photons have very low energy (around a femtoelectronvolt). Microwave energy is produced with klystron and magnetron tubes, and with solid state devices such as Gunn and IMPATT diodes. Electromagnetic Spectrum. Visible light (and near-infrared light) is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another. Quite often, in high energy physics and in medical radiotherapy, very high energy EMR (in the >10 MeV region)—which is of higher energy than any nuclear gamma ray—is not called X-ray or gamma-ray, but instead by the generic term of "high energy photons.". The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation. For example, consider the cosmic microwave background. The distinction between X-rays and gamma rays is partly based on sources: the photons generated from nuclear decay or other nuclear and subnuclear/particle process are always termed gamma rays, whereas X-rays are generated by electronic transitions involving highly energetic inner atomic electrons. [12][13][14] In general, nuclear transitions are much more energetic than electronic transitions, so gamma-rays are more energetic than X-rays, but exceptions exist. Earth's atmosphere is mainly transparent to radio waves, except for layers of charged particles in the ionosphere which can reflect certain frequencies. The EM spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The electromagnetic spectrum describes all of the kinds of light, including those the human eye cannot see. Now this radiation has undergone enough cosmological red shift to put it into the microwave region of the spectrum for observers moving slowly (compared to the speed of light) with respect to the cosmos. One notable use is diagnostic X-ray imaging in medicine (a process known as radiography). The Electromagnetic Spectrum As it was explained in the Introductory Article on the Electromagnetic Spectrum, electromagnetic radiation can be described as a stream of photons, each traveling in a wave-like pattern, carrying energy and moving at the speed of light. For example, Hertz was able to focus the waves using a lens made of tree resin. Although they are emitted and absorbed by short antennas, they are also absorbed by polar molecules, coupling to vibrational and rotational modes, resulting in bulk heating. During the 1860s James Maxwell developed four partial differential equations for the electromagnetic field. Electromagnetic energy passes through space at the speed of light in the [17] Terahertz radiation is strongly absorbed by atmospheric gases, making this frequency range useless for long distance communication. Electromagnetic radiation was first linked to electromagnetism in 1845, when Michael Faraday noticed that the polarization of light traveling through a transparent material responded to a magnetic field (see Faraday effect). The Sun emits its peak power in the visible region, although integrating the entire emission power spectrum through all wavelengths shows that the Sun emits slightly more infrared than visible light. The copper cables (transmission lines) which are used to carry lower frequency radio waves to antennas have excessive power losses at microwave frequencies, and metal pipes called waveguides are used to carry them. 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