Relationship between wave propagation speed frequency

[mnb96]

Hello,
if we assume that the wave propagation-speed in a medium is v, does this imply that there is an "upper-bound" for the maximum frequency that a perturbation can produce?
Or are these totally unrelated quantities?

Thanks!

 

[Naty1]

You can't draw that conclusion...read the first few sentences here and think about light and sound waves for example:http://en.wikipedia.org/wiki/Wave_propagation

 

[mnb96]

ok...I am still confused.

1) First of all: is it true that any medium, for example the air, can "vibrate" at any speed, although the vibration will propagate only at a certain speed (e.g. the speed of sound)?

2) Even if point 1) is correct, think about a source-receiver scenario. A source emits a wave by perturbing the medium at an extremely high frequency. However the vibration propagates through the medium extremely slowly. The receiver will "record" a much lower frequency than the one emitted.

 

[nasu]

ok...I am still confused.

2) Even if point 1) is correct, think about a source-receiver scenario. A source emits a wave by perturbing the medium at an extremely high frequency. However the vibration propagates through the medium extremely slowly. The receiver will "record" a much lower frequency than the one emitted.

The receiver will record the same frequency, only much later, due to the slow propagation.
The propagation speed determines the delay between the signal emission and reception.

 

[PJC01]

I can say that there is indeed a relationship between wave propagation speed and frequency. The propagation speed of a wave in a medium is determined by the properties of that medium, such as its density and elasticity. This speed is also related to the frequency of the wave, which is the number of oscillations per unit time.

In general, the higher the frequency of a wave, the faster it will propagate through a medium. This is because higher frequencies correspond to shorter wavelengths, which means the wave can cover more distance in the same amount of time.

However, there is also a limit to the maximum frequency that a perturbation can produce. This is known as the cutoff frequency or critical frequency. Above this frequency, the wave will not be able to propagate through the medium and will instead be reflected or absorbed. The cutoff frequency is dependent on the properties of the medium, such as its density and elasticity, and can be calculated using mathematical equations.

Therefore, the wave propagation speed and frequency are related, as they both depend on the properties of the medium. However, there is an upper limit to the frequency that a wave can have in a given medium, which is determined by the medium's properties. I hope this helps clarify the relationship between these two quantities.