Doppler effect


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Related to Doppler effect: Doppler radar, CT scan, MRI

Dop·pler effect

 (dŏp′lər)
n.
A change in the observed frequency of a wave, as of sound or light, occurring when the source and observer are in motion relative to each other, with the frequency increasing when the source and observer approach each other and decreasing when they move apart. The motion of the source causes a real shift in frequency of the wave, while the motion of the observer produces only an apparent shift in frequency. Also called Doppler shift.

[After Christian Andreas Doppler (1803-1853), Austrian physicist and mathematician who explained the phenomenon.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Doppler effect

(ˈdɒplə)
n
(General Physics) a phenomenon, observed for sound waves and electromagnetic radiation, characterized by a change in the apparent frequency of a wave as a result of relative motion between the observer and the source. Also called: Doppler shift
[C19: named after C. J. Doppler (1803–53), Austrian physicist]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

Dop′pler effect`

(ˈdɒp lər)
n.
a phenomenon characterized by a change (Dop′pler shift`) in the frequency of waves, as light or sound waves, observed when the wave source is moving relative to the observer.
[1900–05; after C. J. Doppler (1803–53), Austrian physicist]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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Doppler effect
As the source of sound waves (the ambulance) moves closer to the observer, the frequency of the sound waves and pitch of the sound become higher. As the source moves away from the observer, the frequency and pitch become lower.

Dop·pler effect

(dŏp′lər)
The apparent change in the frequency of waves, as of sound or light, when the source of the waves is moving toward or away from an observer.
Did You Know? When a car rushes past you on the road with the driver holding down the horn, you hear the horn change tone: it's higher pitched than normal as the car approaches and lower pitched as it departs. That's because of the Doppler effect. Sound waves spread outward in all directions from the horn. The forward motion of the car compresses the sound waves traveling ahead of the car, making the wavelengths shorter. Sound having shorter wavelengths has higher frequency and therefore higher pitch—what you hear if the car is moving towards you. Behind the car, however, the sound waves are drawn apart. Longer wavelengths mean lower frequency and lower pitch, which is what you hear once the car rushes past. The Doppler effect works on light waves, too; in fact, this was how scientists determined that the universe is expanding. The light from galaxies and other distant celestial objects is shifted toward the red end of the spectrum (a phenomenon called red shift). Red light has the longest wavelengths of visible light. The pioneering astronomer Edwin Hubble reasoned that the red shift was due to the Doppler effect: the galaxies are speeding away from us, drawing out the wavelengths of the light emitted behind them, and the universe as a whole is expanding.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

doppler effect

The phenomenon evidenced by the change in the observed frequency of a sound or radio wave caused by a time rate of change in the effective length of the path of travel between the source and the point of observation.
Dictionary of Military and Associated Terms. US Department of Defense 2005.

döppler effect

Apparent change in the frequency of light waves or sound waves due to the relative motion of the observer and the source of the waves.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.Doppler effect - change in the apparent frequency of a wave as observer and source move toward or away from each other
propagation - the movement of a wave through a medium
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
Translations
Doppler-Effekt
effet Doppler
dopplereffekt

Doppler effect

[ˈdɒplərɪˌfekt] N (Astron) → efecto m Doppler
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005

Doppler effect

Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007

Doppler effect

[ˈdɒplərɪˌfɛkt] n (Phys) → effetto Doppler
Collins Italian Dictionary 1st Edition © HarperCollins Publishers 1995
References in periodicals archive ?
Astronomers bypass this problem by measuring the doppler effect of light from galaxies.
By mapping the shifts in wavelengths of this radio light due to the Doppler effect (light from objects moving toward the Earth is slightly shifted to the "bluer" portion of the spectrum while light from objects moving away is slightly shifted to the "redder" portion), the astronomers could clearly see that the gas is rotating around the black hole.
1842 - Christian Doppler presents his idea, now known as the Doppler Effect, to Royal Bohemian Society.
In monostatic radar, motion of the target towards or away changes the frequency of the reflected signal, this is the Doppler effect, says Chen.
They then used a phenomenon known as the Doppler effect to track the impact of its gravitational pull on its parent star.
While the Doppler Effect is one of the factors that influencing fading which is speed of the mobile.
This is similar to when sound waves change in pitch when a honking car passes by us but this is called the Doppler Effect and is being stated for your understanding and is not to be considered exactly the same as gravitational redshift.
The phase modulator and coherent detection enable the distance and velocity of an object to be determined from a single scan using the Doppler Effect.
The combination of the sonic pulse of the Doppler effect and the released power of a sonic boom inspired our celebration of EV Racing."
A Krypton effect B Doppler effect C Pasteur effect D Newton effect 2.
Key VRTS attributes include the ability to simulate Doppler effect velocity of up to 250 km/ hr, minimum obstacle range of 4 m, object distance resolution down to 10 cm, support for multiple angles of arrival, and variable radar cross sections.

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