The Doppler effect refers to change in the observed frequency of a wave if the observer and source are in relative motion.

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Why does the sound of a tuning fork change as we walk away?

This is a question I got for my class. We have the following situation. We take two tuning forks, we hit them, then we take one of the tuning forks and walk away with it. The sound changes as we walk ...
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Independence of frequency in sound waves?

Why does the frequency of sound wave depend only on the source? Why is the frequency and not any other "quality" independent of everything but the source? And that said, why is velocity and ...
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Special Theory of relativity on electromagnetic waves

Since time slows down and length contracts, when we travel almost at speed of light, if the speed of light (or EM waves) remains same and the wavelength of light remains same, do we measure the ...
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Doppler Effect, Why Can't We Just Add Speed to Argument?

In considering the doppler effect, why can we not just take the distance between the two as a function of time, divide by the wave velocity, and add this as a shift in our time argument of the ...
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Distance to the galaxy which has velocity which is perpendicular to the point of view of the static observer

Let's have the galaxy which has velocity which is perpendicular to the point of view of the static observer in the FLRW universe. It emits the light. There is a given redshift $z_{0}$. It will be easy ...
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Dopler Shift for Reflected Sound Waves

If a car was going at near mach-1 speed heading towards a wall and honked its horn. What frequency would the driver measure the reflected sound wave? I trying to think about this reasonably, but the ...
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Why does a doppler red shift prove expansion?

My question boils down to this. If the Universe was contracting the stars closer to the center would move faster to the middle than stars that were further away from the center. That would also ...
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How can Doppler Shift be applied to Electromagnetic waves

Doppler Shift applies (originally) to mechanical waves. Waves that are propagated in a medium. Can anybody explain to me why EMW can get "Doppler Shifted" when they are self propagating "Vacuum" ...
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Blueshift and increase in energy!

Imagine that there is a car and it is not moving but its headlights are on. There is a wall in front of the car but is very far away. Right now energy is being used only in switching on the ...
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How is mobile communication made possible from airplanes?

I have heard that communication using mobile phones begins to degrade when used on a vehicle moving at speeds above 200 km/hr due to doppler effect as described here (p-22). How is this limitation ...
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Red/Blue Shift in EM Waves

A Doppler weather radar operates at a frequency of 3.40 GHz. The wave from this radar system reflects from an approaching weather system moving with a speed of 39.0 m/s. What is the difference ...
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Senior High School work on Doppler measurements

Sorry this question is really vague- as a result I'm very confused. Perhaps you can help me make sense of it. "Radar measurements: Construct a space-time diagram of the radar tracking of an asteroid ...
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Is redshift the only way by which we can tell that space is expanding?

There's another question on physics.SE whose answer, if I have understood it correctly, explains that the farther the points are in space the faster they are moving away from each other. Actually, ...
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Detecting absolute motion with Doppler (reconciling receiver frequencies)

Suppose a transmitter emits a pulse of light every $T$ seconds. The spacial distance between pulses is $cT$. Suppose the receiver is approaching it with speed $v$. Because, after receiving the ...
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Spectroscopy: clarification about doppler shift

I've just begun to study spectroscopy, and I need a clarification about the Doppler Effect. Considering this graph: could you explain me how I can see the doppler shift related to the deeper peak ...
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Role of time dilation in relativistic beaming

This picture is an excerpt I chose from a Wiki article under "Relativistic beaming" Source: http://en.wikipedia.org/wiki/Relativistic_beaming For theta=0,what I don't understand is why the equation ...
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Radar as range detector between cars-static sender vs dynamic sender

Say I have a radar transmitter on a car,used to detect its distance from a car in front of it by measuring the doppler shift on the reflected wave. i.e Car 1 is the source, its wave gets reflected by ...
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is redshift still true if object emitting is not moving away but the observer is

If something is moving away fast it's color would appear redder than its actual color due to phenomenon known as Doppler effect. But what if the object isn't moving but i am moving away faster would ...
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Are all effects that change color perception examples of redshift/blueshift?

As defined by Wikipedia: In physics (especially astrophysics), redshift happens when light seen coming from an object that is moving away is proportionally increased in wavelength, or shifted to ...