What is Doppler Effect in Physics? -Informative World Network.

 

What is the Doppler Effect in Physics? How does the Doppler effect affect the Sound?

We will learn all of it in a brief explanation about the Doppler effect.

Short Definition of Doppler Effect:-

It is a process in which frequencies of sound change due to the motion towards and away from the observer and source. is called Doppler Effect.

How does the Doppler effect affect the Sound Waves?

When a wave is produced by a source in a medium the wave propagates through the medium at a constant speed, v. When produced by the source, the speed of the wave in that particular medium will not change, until the speed of the source changes

   An interesting phenomenon occurs when the source of a sound is moving with respect to a stationary observer. The above diagram shows a car moving to the right at a constant speed. If the driver presses the horn continuously, then sound waves will leave the car and travel outward in expanding spheres.

To make it simple, assume one sound wave is emitted every second. Each sound wave front moves outward from the location where the car was at the time the wave was emitted. The first sound wave, I,

was emitted when the car was in position I as shown in the diagram. This wave has been expanding for three seconds. The second wave, II, was emitted a second later when the car was at position II. This wave has been moving for two seconds. The third wave, III was emitted when the car was at position III. This wave has been moving for 2 seconds. The third wave, III, was emitted when the car was at position III. This wave has been traveling for only one second.

  The sound of the horn will differ depending on the location of an observer, and the effects observed are known as the Doppler Effect. For an observer in front of the car, the wavelength appears to the shorter wavelengths than they actually are. Since the speed of sound is constant, the shorter wavelength creates a higher frequency, and the horn will sound as though it has a  higher pitch than it actually does. For an observer behind the car, the wavelength appears to be longer than they actually are. 

  The Observer hears a lower frequency with a lower pitch than the horn actually makes. 

Note that the sound of the horn is not changing at all. It merely appears to have a higher frequency and lower wavelength and a longer wavelength moving toward the observer, It also apparently has a lower frequency and longer wavelength when the sound source is moving away from the observer.