So, is the frequency of the wave affected by the change in velocity?If so, how?

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Discussion Overview

The discussion centers around the relationship between wave frequency, wavelength, and velocity in a medium where the density varies with distance. Participants explore how changes in wave speed affect frequency and wavelength, particularly in the context of energy conservation and the properties of wave propagation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how frequency and wavelength change when wave speed increases, suggesting a relationship involving the square root of the change in velocity.
  • Another participant asserts that frequency remains constant, stating it is dependent on the source of vibration rather than the medium.
  • A later reply supports the idea that frequency remains constant due to energy conservation, indicating a belief that changes in frequency would also imply changes in energy.
  • Another participant emphasizes that molecules at an interface must have the same frequency to avoid continuous disturbances, reinforcing the idea that frequency does not change with medium variations.

Areas of Agreement / Disagreement

Participants generally agree that frequency remains constant regardless of changes in wave speed, but the reasoning behind this assertion is not fully resolved, with some participants expressing uncertainty about the underlying principles.

Contextual Notes

There is a lack of consensus on the detailed mechanics of how wavelength might change in response to varying wave speed, and assumptions about energy conservation are not fully explored.

Who May Find This Useful

This discussion may be of interest to students and educators in physics, particularly those exploring wave mechanics and the properties of wave propagation in varying media.

SEZHUR
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I've got a sinking feeling that the answer to this question is blatantly obvious, but here goes:
If a wave of velocity v, frequency f and wavelength \lambda travels through a medium whose density is inversely proportional to distance, such that the further the wave travels the greater the velocity of wave, in what manner do f and \lambda change?

Put more simply, if neither the wavelength nor the frequency is held constant and the wave speed increases, how do the wavelength and the frequency change in order to accomadate the change in velocity.

My guess at an answer is that each changes as the square root of the change in the velocity
Eg. 2v=\sqrt{2}\lambda\sqrt{2}f

Thanks for your time

Ps. How do i get the latex commands to work without them jumping down a line?
 
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Welcome to PF!

Hi SEZHUR! Welcome to PF! :smile:

(write "itex" rather than "tex", and it won't keep starting a new line :wink: …)
SEZHUR said:
If a wave of velocity v, frequency f and wavelength \lambda travels through a medium whose density is inversely proportional to distance, such that the further the wave travels the greater the velocity of wave, in what manner do f and \lambda change?

The frequency stays the same. :smile:
 
Thanks for your response and sorry for the delay in mine.
I spoke to my tutors and they gave the same response you did; upon pushing for a reason it became apparent that the real reason why frequency remains constant is locked up a few levels above me :redface: so for the moment I'm happy to believe it based on energy conservation (if frequency changes then so does energy...)

Finally, let me test out your advice for latex...
v = \lambdaf

Thanks
 
frequency remains constant because it is only dependent on the source of vibration and not on the medium it travels, i guess!
 
Hi SEZHUR! :smile:

Look at two molecules on either side of an interface, almost touching each other …

they must have the same frequency as each other, otherwise you'd have a continuous sliding earthquake at the interface, wouldn't you? :wink:

(And it's the same even if the medium changes gradually rather than suddenly.)
 

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