Attenuation

attenuateattenuatedattenuatingattenuatesAttenuation (electromagnetic radiation)attenuatorlossblockingNatural attenuationnon-attenuating
In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium.wikipedia
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Decibel

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This phenomenon is called acoustic attenuation and is measured in decibels (dBs).
In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels.

Sound

audiosound wavesound waves
For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates.
During propagation, waves can be reflected, refracted, or attenuated by the medium.

Acoustic attenuation

attenuationattenuatedattenuation of sound
This phenomenon is called acoustic attenuation and is measured in decibels (dBs).
Acoustic attenuation in a lossy medium plays an important role in many scientific researches and engineering fields, such as medical ultrasonography, vibration and noise reduction.

Transmission medium

mediumtransmission mediamedia
In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium.
Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer excessively.

Stokes's law of sound attenuation

Stokes' law (sound attenuation)Stokes' law of sound attenuationattenuation
Attenuation is linearly dependent on the medium length and attenuation coefficient, as well as – approximately – the frequency of the incident ultrasound beam for biological tissue (while for simpler media, such as air, the relationship is quadratic).
Stokes's law of sound attenuation is a formula for the attenuation of sound in a Newtonian fluid, such as water or air, due to the fluid's viscosity.

Telecommunication

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In electrical engineering and telecommunications, attenuation affects the propagation of waves and signals in electrical circuits, in optical fibers, and in air.
This is to combat attenuation that can render the signal indistinguishable from the noise.

Attenuation coefficient

absorption coefficientLinear attenuation coefficientattenuation
Attenuation coefficients are used to quantify different media according to how strongly the transmitted ultrasound amplitude decreases as a function of frequency.

Optical attenuator

attenuatorvariable optical attenuators
Electrical attenuators and optical attenuators are commonly manufactured components in this field.

Acoustic rheometer

Longitudinal Rheology Analyzers
There are simple equations that express longitudinal modulus in terms of acoustic properties, sound speed V and attenuation α

Optical fiber

fiber opticfiber opticsfiber-optic
In electrical engineering and telecommunications, attenuation affects the propagation of waves and signals in electrical circuits, in optical fibers, and in air.
Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer.

Absorption (electromagnetic radiation)

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Attenuation decreases the intensity of electromagnetic radiation due to absorption or scattering of photons.
A notable effect (attenuation) is to gradually reduce the intensity of light waves as they propagate through a medium.

Path loss

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See the article on path loss for more information on signal loss in wireless communication.
Path loss, or path attenuation, is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space.

Air mass (astronomy)

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As it penetrates the atmosphere, light is attenuated by scattering and absorption; the thicker atmosphere through which it passes, the greater the attenuation.

Ultrasound

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One area of research in which attenuation plays a prominent role, is in ultrasound physics.

Radiography

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Since the body is made up of various substances with differing densities, Ionising and non-ionising radiation can be used to reveal the internal structure of the body on an image receptor by highlighting these differences using attenuation, or in the case of ionising radiation, the absorption of X-ray photons by the denser substances (like calcium-rich bones).

Extinction (astronomy)

extinctionextinction factorinterstellar extinction
Since blue light is much more strongly attenuated than red light, extinction causes objects to appear redder than expected, a phenomenon referred to as interstellar reddening.

Mean free path

cannot travel very fardistance between collisionsdistance that particles can move without colliding with one another
As photons move through the target material, they are attenuated with probabilities depending on their energy, as a result their distribution changes in process called spectrum hardening.

Weather radar

Doppler weather radarradarDoppler radar
This same effect is an important consideration in weather radar, as raindrops absorb a part of the emitted beam that is more or less significant, depending on the wavelength used.
Another Environment Canada radar, in King City (North of Toronto), was dual-polarized in 2005; it uses a 5 cm wavelength, which experiences greater attenuation.

Environmental remediation

remediationsoil remediationenvironmental cleanup
One disadvantage of this approach is the possibility of decreasing anaerobic contaminant destruction natural attenuation where existing conditions enhance anaerobic bacteria which normally live in the soil prefer a reducing environment.

Transparency and translucency

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This phenomenon has given rise to the production of transparent ceramic materials.
Attenuation in fiber optics, also known as transmission loss, is the reduction in intensity of the light beam (or signal) with respect to distance traveled through a transmission medium.

ITU-R P.525

ITU-R P.525 is the International Telecommunications Union radiocommunications standard for the calculation of free-space attenuation.

Physics

physicistphysicalphysicists
In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium.

Flux

flux densityion fluxflow
In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium.