Acoustics & Physics: Is Frequency Linked to Wave Width?

Click For Summary
Higher frequency sound waves are indeed associated with narrower wavelengths, but the concept of "size" in relation to sound waves is more complex. The discussion highlights that while sound waves can propagate indefinitely, their spatial characteristics are defined by wavelength rather than physical size. The tightness of a sound beam is influenced by diffraction and the aperture of the source, meaning a larger source is needed for a narrower beam. The small size of a needle hydrophone is not directly linked to the frequency but rather to its design for detecting ultrasound waves effectively. Understanding these principles is crucial for projects involving ultrasound measurements in water.
F2fHaziq Zaini 93
Messages
3
Reaction score
0
Is it true that the higher the frequency of sound, the narrower the wave will be?
 
Physics news on Phys.org
F2fHaziq Zaini 93 said:
Is it true that the higher the frequency of sound, the narrower the wave will be?
Welcome to the PF. :smile:

The simple answer to your question is Yes. Have a look at this information page to see if it helps your understanding. Post here in your thread if you have questions about the link.

https://en.wikipedia.org/wiki/Wavelength
 
Thanks Berkeman for the reply. Although I wasnt talking abt the wavelength. More like the size of the sound wave.

You see I am trying to understand the use of a needle hydrophone which is used to detect ultrasound waves underwater. So I am basically trying to find out why it's so small in size. I have heard from my professors that sound waves become narrower, as the frequency increases(Huygens Principle)
 
A wave can't be assigned a 'size'. It can propagate any distance and all waves spread out from the nominal direction they are pointed in. The only spatial quantity is wavelength.
However, you may be referring to the 'tightness' of a beam that can be produced. That is limited by Diffraction and depends mostly on the 'aperture' or width of the source (projector or radio antenna etc). You need a wide source to produce a narrow beam.
Your needle hydrophone is small and will not be very directional. Your professor was probably talking loosely about wavelength which, for sound in water, is a lot greater than it is in air because the wave speed is so much higher.
But, when teachers tell you something that doesn't make sense to you, you should challenge them and ask for clarity. Asking about this particular confusion is fully justified.
PS Your professor is, presumably, a Biologist and not a Physicist, which could explain the problem. :wink:
 
I think I believed him because of the fact that when you look at the size of hydrophones; the higher the frequency, the smaller the size of the hydrophone.Which led me to think that sound at the Mhz range will be pretty small. I actually tried explaining to him that it's probably bcuz of the wavelength.

What should I be reading? So that I can understand why a hydrophone has to be needle-shaped?

Appreciate the help :)
(FYI: I am doing a project that involves measuring the power of ultrasound waves in water)
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
3K
Replies
7
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K
Replies
11
Views
2K
  • · Replies 20 ·
Replies
20
Views
5K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 42 ·
2
Replies
42
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K