Sound waves and amplitudes Problem

  • Thread starter alingy1
  • Start date
  • #1
325
0
1. If there is a sound wave travelling in the air, will the amount of air transported by the wave be proportional to the intensity of the wave?
Here is my answer: yes, because as the energy of the wave is related to the square of the amplitude of oscillations, the more energy you have, the more the wave will be able to travel further and the more amount of air will be affected. My teacher said this is wrong and gave me 0. Why?

2. Is the amplitude independent of the wavelength and frequency?
Here is my answer: yes, the wave speed in the medium determines wavelenght and frequency, but amplitude is separate. I got half points for this one.

What is wrong here?
 

Answers and Replies

  • #2
I can't answer your first one because I haven't done sound stuff in a long time, however, for question two:

Correct: Yes
Incorrect: The wave speed in medium

Amplitude is a measure of how big the wave is. Wave length is the distance between crest-crest or trough-trough and frequency tells us how many waves are passing a point per second. Bringing in medium and wave speed is kind of unrelated to the question so it in a way shows you don't really know what you are talking about.

You can think of it like this.
If you look at a sine graph. The amplitude is 1. (The highest it can be is 1, and lowest is -1)
However if I change the distance between the waves, the amplitude still stays as 1. This is because frequency and wavelength, doesn't change the "size" of the wave, they affect the distance between two points on a wave.

Hopefully I explained that well enough.
 
  • #3
olivermsun
Science Advisor
1,248
118
1. If there is a sound wave travelling in the air, will the amount of air transported by the wave be proportional to the intensity of the wave?
Here is my answer: yes, because as the energy of the wave is related to the square of the amplitude of oscillations, the more energy you have, the more the wave will be able to travel further and the more amount of air will be affected. My teacher said this is wrong and gave me 0. Why?

In a linear acoustic wave in air, the air moves back and forth so there's no net transport (of mass) at all.

The air transported during each back-and-forth motion is affected by the pressure and the velocity in a more complicated way, but I don't think this is what the question is asking.
 

Related Threads on Sound waves and amplitudes Problem

Replies
13
Views
2K
  • Last Post
Replies
2
Views
986
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
7K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
6
Views
2K
  • Last Post
Replies
15
Views
2K
  • Last Post
Replies
2
Views
6K
  • Last Post
Replies
2
Views
4K
  • Last Post
Replies
4
Views
1K
Top