What is the wavelength of the sound wave?

In summary: Given that interference will cause First Max to occur at a certain point, the actual wavelength of the sound wave will be shorter than the hypotenuse calculated above (0.41 meters).
  • #1
Physically Impaired
9
0
Here's the problem:

Two speaks side by side are separated by 1 meter. If the sound intensity is found to reach its first maximum when someone stands 1.0 meter directly in front of one of the speakers ( ie. perpendicular to the line between the speakers) what is the wavelength of the sound wave?

I know that wavelength is velocity over frequency but I don't think that applies here. If I draw a right triangle I can get the hypotenuse which is the distance between the person and the other speaker which is the square root of 2. Then take the difference 1.41 minus 1 = .41 meters. Is this the wavelength?

I'm not sure of my methodology! Help!
 
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  • #2
Use the formula wavelength=dsintheta where theta is the angle that the line between the two sources makes with the sound 'ray' heading toward the source.

Note that you're fudging it a little here - the formula assumes that theta is small and as such, both rays are parallel. Here they're clearly not, but you can get away with it because you're directly in front and the path length is the same for -theta as it is for theta.
 
  • #3
Physically Impaired said:
Here's the problem:

Two speaks side by side are separated by 1 meter. If the sound intensity is found to reach its first maximum when someone stands 1.0 meter directly in front of one of the speakers ( ie. perpendicular to the line between the speakers) what is the wavelength of the sound wave?

I know that wavelength is velocity over frequency but I don't think that applies here. If I draw a right triangle I can get the hypotenuse which is the distance between the person and the other speaker which is the square root of 2. Then take the difference 1.41 minus 1 = .41 meters. Is this the wavelength?

I'm not sure of my methodology! Help!
Your methodology is correct for this case where distances are not large with respect to speaker separation distance. Shown in the drawing below, interference will cause First Max to occur where the path length difference between "A" and "B" is 1.0 λ. The right triangle geometry yields:
λ = √2 - 1.0 = (0.414 meters)

Code:
                 First Max
                    /|
                   / |
                  /  |
                 /   |  
             [COLOR=Red][B]A[/B][/COLOR]  /    | [COLOR=Red][B]B[/B][/COLOR] = 1.0 Meter
               /     |  
              /      |
             /       |
            /________|
           ∪        ∪
            1.0 Meter

Interference will cause First Max to occur where
path length difference between [COLOR=Red]"A"[/COLOR] and [COLOR=Red]"B"[/COLOR] is 1.0 λ.


~~
 
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FAQ: What is the wavelength of the sound wave?

What exactly is a sound wave?

A sound wave is a type of mechanical wave that carries energy through a medium, such as air or water. It is created by a vibrating object, which causes neighboring molecules to also vibrate and pass the energy along.

How is wavelength related to sound waves?

Wavelength is the distance between two consecutive points on a wave that are in phase, or have the same level of energy. In the case of sound waves, it is the distance between two consecutive compressions or rarefactions.

Why is the wavelength of sound waves important?

The wavelength of sound waves is important because it determines the pitch, or frequency, of the sound. Higher frequencies have shorter wavelengths and are perceived as higher-pitched sounds, while lower frequencies have longer wavelengths and are perceived as lower-pitched sounds.

How is the wavelength of sound waves measured?

The wavelength of sound waves can be measured by finding the distance between two consecutive points on a wave that are in phase. This can be done using specialized equipment, such as an oscilloscope, or by using mathematical equations based on the speed of sound and the frequency of the wave.

What factors affect the wavelength of sound waves?

The wavelength of sound waves can be affected by the properties of the medium through which they travel, such as density and temperature. It can also be affected by the frequency of the wave, as higher frequencies have shorter wavelengths and lower frequencies have longer wavelengths.

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