Sound waves and amplitudes Problem

In summary: Perhaps the question is asking if there is a connection between the intensity of the wave (i.e. the energy transported per unit area per unit time) and the amplitude of the oscillations of the air. If that's the case, then yes, there is a relationship - the intensity is proportional to the square of the amplitude. However, this does not necessarily mean that the amount of air transported by the wave is also proportional to the intensity. So while your explanation is correct, it may not directly answer the question. This could be why your teacher marked it wrong.
  • #1
alingy1
325
0
1. If there is a sound wave traveling 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?
 
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  • #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
alingy1 said:
1. If there is a sound wave traveling 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.
 

1. What is a sound wave?

A sound wave is a type of mechanical wave that carries energy through a medium, such as air or water, in the form of vibrations. These vibrations cause the molecules of the medium to compress and expand, creating a series of high and low pressure regions that travel through the medium.

2. What is the relationship between sound waves and amplitude?

The amplitude of a sound wave is the measure of its maximum displacement from its resting position. In other words, it is a measure of the loudness or intensity of the sound. As the amplitude of a sound wave increases, the volume of the sound also increases.

3. How is amplitude measured in sound waves?

Amplitude is typically measured in decibels (dB), which is a logarithmic scale. A sound wave with an amplitude of 0 dB is barely audible to humans, while a sound wave with an amplitude of 120 dB can cause pain and permanent hearing damage.

4. Can sound waves have negative amplitudes?

Yes, sound waves can have negative amplitudes. This means that the particles in the medium are moving in the opposite direction from their resting position. However, in most cases, the amplitude of a sound wave is reported as a positive value since it represents the overall intensity of the sound.

5. How does the amplitude of a sound wave affect its frequency?

The amplitude of a sound wave does not affect its frequency, which is the number of cycles or waves that pass a given point in one second. However, the amplitude can affect the perceived pitch of a sound. A higher amplitude can make a sound seem louder and higher in pitch, while a lower amplitude can make it seem softer and lower in pitch.

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