wave
In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from List of types of equilibrium, equilibrium) of one or more quantities. ''Periodic waves'' oscillate repeatedly about an equilibrium ...
Absorption spectroscopy
Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons ...
Acoustic wave
Acoustic waves are types of waves that propagate through matter—such as gas, liquid, and/or solids—by causing the particles of the medium to compress and expand. These waves carry energy and are characterized by properties like acoustic pres ...
Acoustics
Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician ...
Acousto-optic modulator
An acousto-optic modulator (AOM), also called a Bragg cell or an acousto-optic deflector (AOD), uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency). They are used in lasers ...
Alfvén wave
In plasma physics, an Alfvén wave, named after Hannes Alfvén, is a type of plasma wave in which ions oscillate in response to a restoring force provided by an Magnetic tension force, effective tension on the magnetic field lines.
Definition
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Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of am ...
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Amplitude modulation
Amplitude modulation (AM) is a signal modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the instantaneous amplitude of the wave is varied in proportion t ...
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Animal echolocation
Echolocation, also called bio sonar, is a biological active sonar used by several animal groups, both in the air and underwater. Echolocating animals emit calls and listen to the Echo (phenomenon) , echoes of those calls that return from various ...
Aquamarine Power
Aquamarine Power was a British wave energy company, founded in 2005 to commercialise the Oyster wave energy converter, a device to capture energy from near-shore waves. They tested two versions of the Oyster device at the European Marine Energy ...
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Arrayed waveguide grating Arrayed waveguide gratings (AWG) are commonly used as optical (de)multiplexers in wavelength division multiplexed (WDM) systems. These devices are capable of multiplexing many wavelengths into a single optical fiber, thereby increasing the transm ...
Atomic clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betwee ...
Babinet's principle
In physics, Babinet's principle states that the diffraction pattern from an opaque body is identical to that from an aperture (a hole in a screen) of the same size and shape except for the overall forward beam intensity. It was formulated in the ...
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Backward wave oscillator
A backward wave oscillator (BWO), also called carcinotron or backward wave tube, is a vacuum tube that is used to generate microwaves up to the Terahertz radiation, terahertz range. Belonging to the traveling-wave tube family, it is an electroni ...
Beta wave
Beta waves, or beta rhythm, are neural oscillations (brainwaves) in the brain with a frequency range of between 12.5 and 30 Hz (12.5 to 30 cycles per second). Several different rhythms coexist, with some being inhibitory and others excitory ...
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Black hole
A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...
Bloch's theorem
In condensed matter physics, Bloch's theorem states that solutions to the Schrödinger equation in a periodic potential can be expressed as plane waves modulated by periodic functions. The theorem is named after the Swiss physicist Felix Bloch, ...
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Blueshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...
Bow wave
A bow wave is the wave that forms at the bow (watercraft), bow of a ship when it moves through the water. As the bow wave spreads out, it defines the outer limits of a ship's Wake (physics), wake. A large bow wave slows the ship down, is a risk t ...
Breaking wave
In fluid dynamics and nautical terminology, a breaking wave or breaker is a wave with enough energy to "break" at its peak, reaching a critical level at which linear energy transforms into wave turbulence energy with a distinct forward curve. ...
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Bremsstrahlung
In particle physics, bremsstrahlung (; ; ) is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic ...
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Electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
Burgers' equation
Burgers' equation or Bateman–Burgers equation is a fundamental partial differential equation and convection–diffusion equation occurring in various areas of applied mathematics, such as fluid mechanics, nonlinear acoustics, gas dynamics, and ...
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Business cycle
Business cycles are intervals of general expansion followed by recession in economic performance. The changes in economic activity that characterize business cycles have important implications for the welfare of the general population, governmen ...
Carrier wave
In telecommunications, a carrier wave, carrier signal, or just carrier, is a periodic waveform (usually sinusoidal) that conveys information through a process called ''modulation''. One or more of the wave's properties, such as amplitude or freq ...
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Cherenkov radiation
Cherenkov radiation () is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity (speed of propagation of a wavefro ...
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Chirp
A chirp is a signal in which the frequency increases (''up-chirp'') or decreases (''down-chirp'') with time. In some sources, the term ''chirp'' is used interchangeably with sweep signal. It is commonly applied to sonar, radar, and laser syste ...
Circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, at each point, the electromagnetic field of the wave has a constant magnitude and is rotating at a constant rate in a plane perpendicular to ...
Coherence (physics)
Coherence expresses the potential for two waves to Wave interference, interfere. Two Monochromatic radiation, monochromatic beams from a single source always interfere. Wave sources are not strictly monochromatic: they may be ''partly coherent''. ...
Coherence time
For an electromagnetic wave, the coherence time is the time over which a propagating wave (especially a laser or maser beam) may be considered coherent, meaning that its phase is, on average, predictable.
In long-distance transmission systems ...
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Cold wave
A cold wave (known in some regions as a cold snap, cold spell or Arctic Snap) is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temp ...
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Collimated light
A collimated beam of light or other electromagnetic radiation has parallel ray (optics), rays, and therefore will spread minimally as it propagates. A laser beam is an archetypical example. A perfectly collimated light beam, with no beam divergen ...
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Collimator
A collimator is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spat ...
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Compton effect
Compton scattering (or the Compton effect) is the quantum theory of high frequency photons scattering following an interaction with a charged particle, usually an electron. Specifically, when the photon hits electrons, it releases loosely bound e ...
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Comparison of analog and digital recording
Sound can be recorded and stored and played using either digital or analog techniques. Both techniques introduce errors and distortions in the sound, and these methods can be systematically compared. Musicians and listeners have argued over th ...
Continuous wave
A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. It may refer to e.g. a laser or particl ...
Coronal mass ejection
A coronal mass ejection (CME) is a significant ejection of plasma mass from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understandin ...
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Cosmic microwave background radiation
The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dar ...
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Coulomb wave function
In mathematics, a Coulomb wave function is a solution of the Coulomb wave equation, named after Charles-Augustin de Coulomb. They are used to describe the behavior of charged particles in a Coulomb potential and can be written in terms of confluen ...
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Cutoff frequency
In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced ( attenuated or reflected) rather than ...
Dielectric waveguide
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light g ...
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Diffraction
Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation ...
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Direction finding
Direction finding (DF), radio direction finding (RDF), or radiogoniometry is the use of radio waves to determine the direction to a radio source. The source may be a cooperating radio transmitter or may be an inadvertent source, a naturall ...
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Dispersion (optics)
Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Sometimes the term chromatic dispersion is used to refer to optics specifically, as opposed to wave propagation in general. A medium having this common ...
Dispersion relation
In the physical sciences and electrical engineering, dispersion relations describe the effect of dispersion on the properties of waves in a medium. A dispersion relation relates the wavelength or wavenumber of a wave to its frequency. Given the ...
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Dominant wavelength
In color science, the dominant wavelength is a method of approximating a color's hue. Along with purity, it makes up one half of the Helmholtz coordinates. The dominant wavelength of a given color is defined to be the wavelength of monochromatic ...
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Doppler effect
The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described ...
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Doppler radar
A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the fre ...
Earthquake
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...
Echo sounding
Echo sounding or depth sounding is the use of sonar for ranging, normally to determine the depth (coordinate), depth of water (bathymetry). It involves transmitting acoustic waves into water and recording the time interval between emission and ...
Eddy (fluid dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current (water), current created when the fluid is in a Turbulence, turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstre ...
Ekman layer
Ekman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman transport is a component of wind-driven ocean current. Ekman transport occurs ...
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Ekman spiral
Ekman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman transport is a component of wind-driven ocean current. Ekman transport occurs ...
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Ekman transport
Ekman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman transport is a component of wind-driven ocean current. Ekman transport occurs w ...
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El Niño–Southern Oscillation
El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variation in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cyc ...
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Electroencephalography
Electroencephalography (EEG)
is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignal, bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in ...
Electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
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Electromagnetic wave
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ...
Electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...
Emission spectrum
The emission spectrum of a chemical element or chemical compound is the Spectrum (physical sciences), spectrum of frequencies of electromagnetic radiation emitted due to electrons making a atomic electron transition, transition from a high energ ...
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Envelope (waves)
In physics and engineering, the envelope of an oscillating signal is a smooth curve outlining its extremes. The envelope thus generalizes the concept of a constant amplitude into an instantaneous amplitude. The figure illustrates a modulated sine w ...
Evanescent wave
In electromagnetics, an evanescent field, or evanescent wave, is an oscillating electric and/or magnetic field that does not propagate as an electromagnetic wave but whose energy is spatially concentrated in the vicinity of the source (oscilla ...
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Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of p ...
Fabry–Pérot interferometer
In optics, a Fabry–Pérot interferometer (FPI) or etalon is an optical cavity made from two parallel reflecting surfaces (i.e.: thin mirrors). Optical waves can pass through the optical cavity only when they are in resonance with it. It is ...
Fetch (geography)
In oceanography wind fetch, also known as fetch length or simply fetch, is the length of water over which a given wind has blown without obstruction. Fetch is used in geography and meteorology and its effects are usually associated with sea st ...
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Fourier series
A Fourier series () is an Series expansion, expansion of a periodic function into a sum of trigonometric functions. The Fourier series is an example of a trigonometric series. By expressing a function as a sum of sines and cosines, many problems ...
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Fraunhofer diffraction
In optics, the Fraunhofer diffraction equation is used to model the diffraction of waves when plane waves are incident on a diffracting object, and the diffraction pattern is viewed at a sufficiently long distance (a distance satisfying Fraunhofer ...
French New Wave
The New Wave (, ), also called the French New Wave, is a French European art cinema, art film movement that emerged in the late 1950s. The movement was characterized by its rejection of traditional filmmaking conventions in favor of experimentat ...
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Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...
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Frequency modulation
Frequency modulation (FM) is a signal modulation technique used in electronic communication, originally for transmitting messages with a radio wave. In frequency modulation a carrier wave is varied in its instantaneous frequency in proporti ...
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Fresnel diffraction
In optics, the Fresnel diffraction equation for near-field diffraction is an approximation of the Kirchhoff's diffraction formula, Kirchhoff–Fresnel diffraction that can be applied to the propagation of waves in the near and far field, near fi ...
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Fresnel equations
The Fresnel equations (or Fresnel coefficients) describe the reflection and transmission of light (or electromagnetic radiation in general) when incident on an interface between different optical media. They were deduced by French engineer and ...
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Fresnel integral
250px,
Plots of and . The maximum of is about . If the integrands of and were defined using instead of , then the image would be scaled vertically and horizontally (see below).
The Fresnel integrals and are two transcendental functions n ...
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Fresnel lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens (optics), lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.
The simpler Dioptrics, d ...
Fresnel rhomb
A Fresnel rhomb is an optical prism that introduces a 90° phase difference between two perpendicular components of polarization, by means of two total internal reflections. If the incident beam is linearly polarized at 45° to the plane of in ...
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Fresnel zone
A Fresnel zone ( ), named after physicist Augustin-Jean Fresnel, is one of a series of confocal prolate ellipsoidal regions of space between and around a transmitter and a receiver. The size of the calculated Fresnel zone at any particular di ...
Fundamental frequency
The fundamental frequency, often referred to simply as the ''fundamental'' (abbreviated as 0 or 1 ), is defined as the lowest frequency of a Periodic signal, periodic waveform. In music, the fundamental is the musical pitch (music), pitch of a n ...
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Gamma ray
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...
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Gamma ray burst
In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme electromagnetic emissions are second ...
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Gamma wave
A gamma wave or gamma rhythm is a pattern of neural oscillation in humans with a frequency between 30 and 100 Hz, the 40 Hz point being of particular interest. Gamma waves with frequencies between 30 and 70 hertz may be classified as low ...
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Gaussian beam
In optics, a Gaussian beam is an idealized beam of electromagnetic radiation whose amplitude envelope in the transverse plane is given by a Gaussian function; this also implies a Gaussian intensity (irradiance) profile. This fundamental (or ...
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Geometric optics
Geometry (; ) is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. Geometry is, along with arithmetic, one of the oldest branches of mathematics. A mathematician ...
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Geometrical optics
Geometrical optics, or ray optics, is a model of optics that describes light Wave propagation, propagation in terms of ''ray (optics), rays''. The ray in geometrical optics is an abstract object, abstraction useful for approximating the paths along ...
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Geostrophic current
A geostrophic current is an oceanic current in which the pressure gradient force is balanced by the Coriolis effect. The direction of geostrophic flow is parallel to the isobars, with the high pressure to the right of the flow in the Norther ...
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Gravitational radiation
Gravitational waves are oscillations of the gravitational field that travel through space at the speed of light; they are generated by the relative motion of gravitating masses. They were proposed by Oliver Heaviside in 1893 and then later by ...
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Gravity wave
In fluid dynamics, gravity waves are waves in a fluid medium or at the interface between two media when the force of gravity or buoyancy tries to restore equilibrium. An example of such an interface is that between the atmosphere and the oc ...
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Groundwave
Ground wave is a mode of radio propagation that consists of currents traveling through the earth. Ground waves propagate parallel to and adjacent to the surface of the Earth, and are capable of covering long distances by diffracting around the ...
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Group delay
In signal processing, group delay and phase delay are functions that describe in different ways the delay times experienced by a signal’s various sinusoidal frequency components as they pass through a linear time-invariant (LTI) system (such as ...
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Group velocity
The group velocity of a wave is the velocity with which the overall envelope shape of the wave's amplitudes—known as the ''modulation'' or ''envelope (waves), envelope'' of the wave—propagates through space.
For example, if a stone is thro ...
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Harmonic
In physics, acoustics, and telecommunications, a harmonic is a sinusoidal wave with a frequency that is a positive integer multiple of the ''fundamental frequency'' of a periodic signal. The fundamental frequency is also called the ''1st har ...
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Heat wave
A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather generally considered to be at least ''five consecutive days''. A heat wave is usually measured relative to the usual climate in the area and ...
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Holography
Holography is a technique that allows a wavefront to be recorded and later reconstructed. It is best known as a method of generating three-dimensional images, and has a wide range of other uses, including data storage, microscopy, and interfe ...
Hurricane
A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its ...
Hydrography
Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary ...
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Hydropower
Hydropower (from Ancient Greek -, "water"), also known as water power or water energy, is the use of falling or fast-running water to Electricity generation, produce electricity or to power machines. This is achieved by energy transformation, ...
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Hyperbolic partial differential equation
In mathematics, a hyperbolic partial differential equation of order n is a partial differential equation (PDE) that, roughly speaking, has a well-posed initial value problem for the first n - 1 derivatives. More precisely, the Cauchy problem can ...
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In phase
In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a s ...
Interference (wave propagation)
In physics, interference is a phenomenon in which two coherent waves are combined by adding their intensities or displacements with due consideration for their phase difference. The resultant wave may have greater amplitude (constructive in ...
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Interferometry
Interferometry is a technique which uses the ''interference (wave propagation), interference'' of Superposition principle, superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important inves ...
Irradiance
In radiometry, irradiance is the radiant flux ''received'' by a ''surface'' per unit area. The SI unit of irradiance is the watt per square metre (symbol W⋅m−2 or W/m2). The CGS unit erg per square centimetre per second (erg⋅cm−2⋅s−1) ...
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Japanese New Wave
The is a term for a group of loosely-connected Japanese films and filmmakers between the late 1950s and part of the 1970s. The most prominent representatives include directors Nagisa Ōshima, Yoshishige Yoshida, Masahiro Shinoda and Shōhei I ...
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Kelvin wave
A Kelvin wave is a wave in the ocean, a large lake or the atmosphere that balances the Earth's Coriolis force against a topographic boundary such as a coastline, or a waveguide such as the equator. A feature of a Kelvin wave is that it is non-d ...
Landau damping
In physics, Landau damping, named after its discoverer,Landau, L. "On the vibration of the electronic plasma". ''JETP'' 16 (1946), 574. English translation in ''J. Phys. (USSR)'' 10 (1946), 25. Reproduced in Collected papers of L.D. Landau, edited ...
Linear elasticity
Linear elasticity is a mathematical model of how solid objects deform and become internally stressed by prescribed loading conditions. It is a simplification of the more general nonlinear theory of elasticity and a branch of continuum mechani ...
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Linear polarization
In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. The term ''linear polarizati ...
Longitudinal wave
Longitudinal waves are waves which oscillate in the direction which is parallel to the direction in which the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal ...
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Longwave
In radio, longwave (also spelled long wave or long-wave and commonly abbreviated LW) is the part of the radio spectrum with wavelengths longer than what was originally called the medium-wave (MW) broadcasting band. The term is historic, dati ...
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Love wave
In elastodynamics, Love waves, named after Augustus Edward Hough Love, are horizontally polarized surface waves. The Love wave is a result of the interference of many shear waves ( S-waves) guided by an elastic layer, which is ''welded'' to a ...
Mach–Zehnder interferometer
The Mach–Zehnder interferometer is a device used to determine the relative phase shift variations between two collimated beams derived by splitting light from a single source. The interferometer has been used, among other things, to measure p ...
Magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...
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Magnetosonic wave
In physics, magnetosonic waves, also known as magnetoacoustic waves, are low-frequency Compression (physics), compressive waves driven by mutual interaction between an electrically conducting fluid and a magnetic field. They are associated with Co ...
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Matter wave
Matter waves are a central part of the theory of quantum mechanics, being half of wave–particle duality. At all scales where measurements have been practical, matter exhibits wave-like behavior. For example, a beam of electrons can be diffract ...
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Maxwell's equations
Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, Electrical network, electr ...
Mechanical wave
In physics, a mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a material medium.Giancoli, D. C. (2009) Physics for scientists & engineers with modern physics (4th ed.). Upper Saddle River, N.J. ...
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Medical ultrasonography
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...
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Mediumwave
Medium wave (MW) is a part of the medium frequency (MF) radio band used mainly for AM broadcasting, AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. Duri ...
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Megatsunami
A megatsunami is an incredibly large wave created by a substantial and sudden displacement of material into a body of water.
Megatsunamis have different features from ordinary tsunamis. Ordinary tsunamis are caused by underwater tectonic activi ...
Microwave
Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
Microwave oven
A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...
Mie scattering
In electromagnetism, the Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The sol ...
Modulation
Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information.
The process encodes information in form of the modulation or message ...
Monochromator
A monochromator is an optics, optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input. The name is .
Uses
A device that can ...
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Moonlight
Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes.
History
The ancient Greek philosopher Anaxagoras was aware that "''the sun provides the moon with its ...
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Morning Glory cloud
The Morning Glory cloud is a rare List of meteorological phenomena, meteorological phenomenon consisting of a low-level atmospheric solitary wave and associated cloud, occasionally observed in different locations around the world. The wave o ...
Multipath propagation
In radio communication, multipath is the propagation phenomenon that results in radio signals reaching the receiving antenna by two or more paths. Causes of multipath include atmospheric ducting, ionospheric reflection and refraction, and ...
Neutron
The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...
New Wave (science fiction)
The New Wave was a science fiction style of the 1960s and 1970s, characterized by a great degree of experimentation with the form and content of stories, greater imitation of the styles of non-science fiction literature, and an emphasis on the p ...
New wave music
New wave is a music genre that encompasses pop music, pop-oriented styles from the 1970s through the 1980s. It is considered a lighter and more melodic "broadening of Punk subculture, punk culture". It was originally used as a catch-all fo ...
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New wave of American heavy metal
The new wave of American heavy metal (also known as NWOAHM and new wave of American metal) was a heavy metal music movement that originated in the United States during the early–mid 1990s and expanded most in the early to mid-2000s. Some of th ...
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New wave of British heavy metal
The new wave of British heavy metal (often abbreviated as NWOBHM) was a nationwide musical movement that began in England in the mid-1970s and achieved international attention by the early 1980s. Editor Alan Lewis (music journalist), Alan Lew ...
Nonlinear Schrödinger equation
In theoretical physics, the (one-dimensional) nonlinear Schrödinger equation (NLSE) is a nonlinear variation of the Schrödinger equation. It is a classical field equation whose principal applications are to the propagation of light in nonli ...
Normal mode
A normal mode of a dynamical system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. The free motion described by the normal modes takes place at fixed frequencies ...
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Ocean surface wave
In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of Body of water, bodies of water as a result of the wind blowing over the water's surface. The contact distance in the wind directi ...
Optical fiber
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...
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Optical waveguide
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid ligh ...
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Oscillon
In physics, an oscillon is a soliton-like phenomenon that occurs in granular and other dissipative media. Oscillons in granular media result from vertically vibrating a plate with a layer of uniform particles placed freely on top. When the sinuso ...
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Out of phase
In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a s ...
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Outgoing longwave radiation
In climate science, longwave radiation (LWR) is electromagnetic radiation, electromagnetic thermal radiation emitted by Earth's surface, atmosphere, and clouds. It is also referred to as terrestrial radiation. This radiation is in the infrared p ...
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Overtone
An overtone is any resonant frequency above the fundamental frequency of a sound. (An overtone may or may not be a harmonic) In other words, overtones are all pitches higher than the lowest pitch within an individual sound; the fundamental i ...
P-wave
A P wave (primary wave or pressure wave) is one of the two main types of elastic body waves, called seismic waves in seismology. P waves travel faster than other seismic waves and hence are the first signal from an earthquake to arrive at any ...
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Parabolic reflector
A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a Mirror, reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface ge ...
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Periodic function
A periodic function, also called a periodic waveform (or simply periodic wave), is a function that repeats its values at regular intervals or periods. The repeatable part of the function or waveform is called a ''cycle''. For example, the t ...
Phase (waves)
In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a s ...
Phase modulation
Phase modulation (PM) is a signal modulation method for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Phase modulation is one of the two principal f ...
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Phase velocity
The phase velocity of a wave is the rate at which the wave propagates in any medium. This is the velocity at which the phase of any one frequency component of the wave travels. For such a component, any given phase of the wave (for example, t ...
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Phonon
A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids. In the context of optically trapped objects, the quantized vibration mode can be defined a ...
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Photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can ...
Planck constant
The Planck constant, or Planck's constant, denoted by h, is a fundamental physical constant of foundational importance in quantum mechanics: a photon's energy is equal to its frequency multiplied by the Planck constant, and the wavelength of a ...
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Planck's law
In physics, Planck's law (also Planck radiation law) describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature , when there is no net flow of matter or energy between the ...
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Plane wave
In physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of ...
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Polarization (waves)
, or , is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. One example of a polariz ...
Proton
A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an e ...
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Pulsar
A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
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Pulsar wind nebula
A pulsar wind nebula (PWN, plural PWNe), sometimes called a plerion (derived from the Greek "πλήρης", ''pleres'', meaning "full"), is a type of nebula sometimes found inside the shell of a supernova remnant (SNR), powered by winds generate ...
Pulse-density modulation
Pulse-density modulation (PDM) is a form of modulation used to represent an analog signal with a binary signal. In a PDM signal, specific amplitude values are not encoded into codewords of pulses of different weight as they would be in pulse ...
Q
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QT interval
The QT interval is a measurement made on an Electrocardiography, electrocardiogram used to assess some of the electrical properties of the heart. It is calculated as the time from the start of the QRS complex, Q wave to the end of the T wave, an ...
Quadrature amplitude modulation
Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signa ...
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Quantum optics
Quantum optics is a branch of atomic, molecular, and optical physics and quantum chemistry that studies the behavior of photons (individual quanta of light). It includes the study of the particle-like properties of photons and their interaction ...
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Quantum tunneling
In physics, a quantum (: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization". This me ...
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Quantum Zeno effect
In quantum mechanics, frequent measurements cause the quantum Zeno effect, a reduction in transitions away from the systems initial state, slowing a systems time evolution.
Sometimes this effect is interpreted as "a system cannot change while you ...
R
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Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
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Radar astronomy
Radar astronomy is a technique of observing nearby astronomical objects by reflecting radio waves or microwaves off target objects and analyzing their reflections. Radar astronomy differs from ''radio astronomy'' in that the latter is a passive ob ...
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Radar cross section
Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected.
An object reflects a limited amount of radar energy b ...
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Radar gun
A radar speed gun, also known as a radar gun, speed gun, or speed trap gun, is a device used to measure the speed of moving objects. It is commonly used by police to check the speed of moving vehicles while conducting Traffic police, traffic enf ...
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Radio propagation
Radio propagation is the behavior of radio waves as they travel, or are wave propagation, propagated, from one point to another in vacuum, or into various parts of the atmosphere.
As a form of electromagnetic radiation, like light waves, radio w ...
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Radio wave
Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths g ...
Rayleigh scattering
Rayleigh scattering ( ) is the scattering or deflection of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scat ...
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Rayleigh wave
Rayleigh waves are a type of surface acoustic wave that travel along the surface of solids. They can be produced in materials in many ways, such as by a localized impact or by Piezoelectricity, piezo-electric Interdigital transducer, transduction, ...
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Rayleigh–Jeans law
In physics, the Rayleigh–Jeans law is an approximation to the spectral radiance of electromagnetic radiation as a function of wavelength from a black body at a given temperature through classical arguments. For wavelength ''λ'', it is
B_\l ...
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Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...
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Reflection coefficient
In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected ...
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Reflection seismology
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflection (physics), reflected seismic waves. The method requir ...
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Refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...
Resonance
Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...
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Resonator
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a reso ...
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Ring laser gyroscope
A ring laser gyroscope (RLG) consists of a ring laser having two independent counter-propagating resonant modes over the same path; the difference in phase is used to detect rotation. It operates on the principle of the Sagnac effect which shi ...
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Ring modulation
In electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal. One signal, called the carrier, is typically a sine wave or another simple w ...
Rip current
A rip current (or just rip) is a specific type of water current that can occur near beaches where waves break. A rip is a strong, localized, and narrow current of water that moves directly away from the shore by cutting through the lines of bre ...
Rossby wave
Rossby waves, also known as planetary waves, are a type of inertial wave naturally occurring in rotating fluids. They were first identified by Sweden-born American meteorologist Carl-Gustaf Arvid Rossby in the Earth's atmosphere in 1939. They ...
Rydberg constant
In spectroscopy, the Rydberg constant, symbol R_\infty for
heavy atoms or R_\text for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first ...
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Rydberg formula
In atomic physics, the Rydberg formula calculates the wavelengths of a spectral line in many chemical elements. The formula was primarily presented as a generalization of the Balmer series for all atomic electron transitions of hydrogen. It was ...
S
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S-wave
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In seismology and other areas involving elastic waves, S waves, secondary waves, or shear waves (sometimes called elastic S waves) are a type of elastic wave and are one of the two main types of elastic body waves, so named because t ...
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Sampling (signal processing)
In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a sound wave to a sequence of "samples".
A sample is a value of the signal at a point in time and/or ...
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Sawtooth wave
The sawtooth wave (or saw wave) is a kind of non-sinusoidal waveform. It is so named based on its resemblance to the teeth of a plain-toothed saw with a zero rake angle. A single sawtooth, or an intermittently triggered sawtooth, is called a ...
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Schrödinger equation
The Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after E ...
Seiche
A seiche ( ) is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors, caves, and seas. The key requirement for formatio ...
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Seismic wave
A seismic wave is a mechanical wave of acoustic energy that travels through the Earth or another planetary body. It can result from an earthquake (or generally, a quake), volcanic eruption, magma movement, a large landslide and a large ma ...
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Seismograph
A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The out ...
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Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic ...
Shock wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
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Shortwave radio
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the High frequency, high frequency band (HF), which extends from 3 to 30& ...
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Signal velocity
The signal velocity is the speed at which a wave carries information. It describes how quickly a message can be communicated (using any particular method) between two separated parties. No signal velocity can exceed the speed of a light pulse in a ...
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Significant wave height
In physical oceanography, the significant wave height (SWH, HTSGW or ''H''s)
is defined traditionally as the mean ''wave height'' (trough (physics), trough to crest (physics), crest) of the highest third of the ocean surface wave, waves (''H''1/ ...
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Sine wave
A sine wave, sinusoidal wave, or sinusoid (symbol: ∿) is a periodic function, periodic wave whose waveform (shape) is the trigonometric function, trigonometric sine, sine function. In mechanics, as a linear motion over time, this is ''simple ...
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Single-sideband modulation
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of signal modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitu ...
Skywave
In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvatur ...
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Slow-wave potential
A slow-wave potential is a rhythmic electrophysiological event in the gastrointestinal tract. The normal conduction of slow waves is one of the key regulators of gastrointestinal motility. Slow waves are generated and propagated by a class of pac ...
Soliton
In mathematics and physics, a soliton is a nonlinear, self-reinforcing, localized wave packet that is , in that it preserves its shape while propagating freely, at constant velocity, and recovers it even after collisions with other such local ...
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Sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...
Sound wave
In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the ...
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Spark-gap transmitter
A spark-gap transmitter is an obsolete type of transmitter, radio transmitter which generates radio waves by means of an electric spark."Radio Transmitters, Early" in Spark-gap transmitters were the first type of radio transmitter, and were the m ...
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Spectroscopy
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum.
Spectro ...
Speed of light
The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time i ...
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Speed of sound
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elasticity (solid mechanics), elastic medium. More simply, the speed of sound is how fast vibrations travel. At , the speed of sound in a ...
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Spike-and-wave
Spike-and-wave is a pattern of the electroencephalogram (EEG) typically observed during epileptic seizures. A spike-and-wave discharge is a regular, symmetrical, generalized EEG pattern seen particularly during absence epilepsy, also known as ...
Square wave Square wave may refer to:
*Square wave (waveform)
A square wave is a non-sinusoidal waveform, non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same ...
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Standing wave
In physics, a standing wave, also known as a stationary wave, is a wave that oscillates in time but whose peak amplitude profile does not move in space. The peak amplitude of the wave oscillations at any point in space is constant with respect t ...
Stefan–Boltzmann law
The Stefan–Boltzmann law, also known as ''Stefan's law'', describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Lu ...
Subharmonic
In music, the undertone series or subharmonic series is a sequence of notes that results from inverting the intervals of the overtone series. While overtones naturally occur with the physical production of music on instruments, undertones mus ...
Superposition principle
The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So th ...
Surface wave
In physics, a surface wave is a mechanical wave that propagates along the Interface (chemistry), interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occu ...
Surface-wave magnitude
The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This mag ...
Surfing
Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suita ...
T wave
In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the ''absolute refractory period''. The last half of the T wav ...
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Terrestrial gamma-ray flash
A terrestrial gamma-ray flash (TGF), also known as dark lightning, is a burst of gamma rays produced in Earth's atmosphere. TGFs have been recorded to last 0.2 to 3.5 milliseconds, and have energies of up to 20 million electronvolts. It is spe ...
Tidal bore
A tidal bore, often simply given as bore in context, is a tidal phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay, reversing the direction of the river or bay's cu ...
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Tidal power
Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods.
Although not yet widely used, tidal energy has the potential for future electricity generation. T ...
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables ...
Transverse mode
A transverse mode of electromagnetic radiation is a particular electromagnetic field pattern of the radiation in the plane perpendicular (i.e., transverse) to the radiation's propagation direction. Transverse modes occur in radio waves and micr ...
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Transverse wave
In physics, a transverse wave is a wave that oscillates perpendicularly to the direction of the wave's advance. In contrast, a longitudinal wave travels in the direction of its oscillations. All waves move energy from place to place without t ...
Traveling-wave tube
A traveling-wave tube (TWT, pronounced "twit") or traveling-wave tube amplifier (TWTA, pronounced "tweeta") is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. It was invented ...
Trigonometric function
In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all ...
Tsunami
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
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Turbidity current
A turbidity current is most typically an Ocean current, underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in ...
U
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Ultra low frequency
Ultra low frequency (ULF) is the ITU designation for the frequency range of electromagnetic waves between 300 hertz and 3 kilohertz, corresponding to wavelengths between 1,000 and 100 km. In magnetosphere science and seismology, alternative ...
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Ultrasound
Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...
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Ultraviolet catastrophe
The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century and early 20th century classical physics that an ideal black body at thermal equilibrium would emit an unbounded quantity of en ...
Undular bore
In meteorology, an undular bore is a wave disturbance in the Earth's atmosphere and can be seen through unique cloud formations. They normally occur within an area of the atmosphere which is stable in the low levels after an outflow boundary or ...
Voltage standing wave ratio
In radio engineering and telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the tra ...
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Vortex
In fluid dynamics, a vortex (: vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in th ...
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Vorticity
In continuum mechanics, vorticity is a pseudovector (or axial vector) field that describes the local spinning motion of a continuum near some point (the tendency of something to rotate), as would be seen by an observer located at that point an ...
Wave (audience)
The wave (also Mexican wave outside North America) is a type of metachronal rhythm achieved in a packed stadium or other large seated venue, when successive groups of spectators briefly stand and raise their arms. Immediately upon stretching to ...
Wave drag
In aeronautics, wave drag is a component of the aerodynamic drag
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding flu ...
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Wave equation
The wave equation is a second-order linear partial differential equation for the description of waves or standing wave fields such as mechanical waves (e.g. water waves, sound waves and seismic waves) or electromagnetic waves (including light ...
Wave function
In quantum physics, a wave function (or wavefunction) is a mathematical description of the quantum state of an isolated quantum system. The most common symbols for a wave function are the Greek letters and (lower-case and capital psi (letter) ...
Wave height
In fluid dynamics, the wave height of a surface wave is the difference between the elevations of a crest and a neighboring trough. ''Wave height'' is a term used by mariners, as well as in coastal, ocean and naval engineering.
At sea, the ...
Wave packet
In physics, a wave packet (also known as a wave train or wave group) is a short burst of localized wave action that travels as a unit, outlined by an Envelope (waves), envelope. A wave packet can be analyzed into, or can be synthesized from, a ...
Wave pool
A wave pool is a swimming pool in which there are artificially generated, large waves, similar to those of the ocean. Wave pools are often a major feature of water parks, both indoors and outdoors, as well as some leisure centres.
History
Th ...
Wave power
Wave power is the capture of energy of wind waves to do useful mechanical work, work – for example, electricity generation, desalination, or pumping water. A machine that exploits wave power (physics), power is a wave energy converter (WEC).
W ...
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Wave propagation
In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. '' Periodic waves'' oscillate repeatedly about an equilibrium (resting) value at some f ...
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Wave shoaling
In fluid dynamics, wave shoaling is the effect by which ocean surface waves, surface waves, entering shallower water, change in wave height. It is caused by the fact that the group velocity, which is also the wave-energy transport velocity, decr ...
Wave vector
In physics, a wave vector (or wavevector) is a vector used in describing a wave, with a typical unit being cycle per metre. It has a magnitude and direction. Its magnitude is the wavenumber of the wave (inversely proportional to the wavelength) ...
Wave-making resistance
Wave-making resistance or wave resistance is a form of Drag (physics), drag that affects any object moving on a surface of a fluid, such as boats and ships moving on the surface of water, and reflects the energy required to push the water out of ...
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Waveform
In electronics, acoustics, and related fields, the waveform of a signal is the shape of its Graph of a function, graph as a function of time, independent of its time and Magnitude (mathematics), magnitude Scale (ratio), scales and of any dis ...
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Waveform monitor
A waveform monitor is a special type of oscilloscope used in television production applications. It is typically used to measure and display the level, or voltage, of a video signal with respect to time.
The level of a video signal usually corre ...
Wavefront
In physics, the wavefront of a time-varying ''wave field (physics), field'' is the set (locus (mathematics), locus) of all point (geometry), points having the same ''phase (waves), phase''. The term is generally meaningful only for fields that, a ...
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Wavefunction
In quantum physics, a wave function (or wavefunction) is a mathematical description of the quantum state of an isolated quantum system. The most common symbols for a wave function are the Greek letters and (lower-case and capital psi (letter) ...
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Wavefunction collapse
In various interpretations of quantum mechanics, wave function collapse, also called reduction of the state vector, occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to i ...
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Waveguide
A waveguide is a structure that guides waves by restricting the transmission of energy to one direction. Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency w ...
Waveguide (electromagnetism)
In radio-frequency engineering and communications system engineering, communications engineering, a waveguide is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line mostly at microwave frequenci ...
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Waveguide (optics)
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light ...
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Waveguide flange
A waveguide flange is a connector for joining sections of waveguide (electromagnetism), waveguide, and is essentially the same as a pipe flange—a ''waveguide'', in the context of this article, being a hollow metal conduit for microwave energy. ...
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Wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats.
In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...
Wavelength-division multiplexing
In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This techn ...
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Wavelet
A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases or decreases, and then returns to zero one or more times. Wavelets are termed a "brief oscillation". A taxonomy of wavelets has been established, based on the n ...
Wavenumber
In the physical sciences, the wavenumber (or wave number), also known as repetency, is the spatial frequency of a wave. Ordinary wavenumber is defined as the number of wave cycles divided by length; it is a physical quantity with dimension of ...
Wave–particle duality
Wave–particle duality is the concept in quantum mechanics that fundamental entities of the universe, like photons and electrons, exhibit particle or wave (physics), wave properties according to the experimental circumstances. It expresses the in ...
Wien approximation
Wien's approximation (also sometimes called Wien's law or the Wien distribution law) is a law of physics used to describe the spectrum of thermal radiation (frequently called the blackbody function). This law was first derived by Wilhelm Wien in ...
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Wien's displacement law
In physics, Wien's displacement law states that the black-body radiation curve for different temperatures will peak at different wavelengths that are inversely proportional to the temperature. The shift of that peak is a direct consequence of ...
Wind wave
In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result of the wind blowing over the water's surface. The contact distance in the direction of the wind is ...
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Windsurfing
Windsurfing is a wind-propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the Californian aerospace and surf culture. Windsurfing gain ...
X-ray
An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
Zigzag
A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines; it can be described as both jagged and fairly regular.
In geometry, this pattern is described as a ...
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Zodiacal light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direct ...