Points of destructive interference of sound waves?

In summary, the conversation is about two speakers emitting sound waves with a frequency of 340Hz and a listener walking towards one of the speakers. The question is how many points of destructive interference will be observed. The condition for destructive interference is (delta L/wavelength) = n*0.5, and in this case, the initial value of delta L is 1 and the final value is 3. The vertical distance between the two sources is also mentioned, but the final answer is not 4 as previously thought, but rather 2. The conversation ends with the agreement that the answer is indeed 2.
  • #1
Maged Saeed
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Homework Statement


Two speakers (S1,S2), emitting sound waves of frequency 340Hz and separated by a distance of 3 m, are driven by the same oscillator. A listener starts walking from point A to S2 Along the line that joins A and S2> How many points of destructive interference will be observe? Speed of sound in are is 340 m/s

Homework Equations


w=v/f

The Attempt at a Solution


Although, it seems quite easy,I've tried to solve it many times with no reasonable result,
Wavelength will be 1 meter. And I don't know how to do after that.

the right answer is 4 but how it comes??
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  • #2
What is the condition for destructive interference?
This condition has one parameter that will vary as you go towards S1. What is its initial and final value?
 
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  • #3
mfb said:
What is the condition for destructive interference?
This condition has one parameter that will vary as you go towards S1. What is its initial and final value?
The condition says :
for a destructive interference, (delta L/wavelength)=n.0.5
But how can I apply it here?

The initial value of delta L equals to 1 and the final value equals 1.
 
  • #4
Maged Saeed said:
The initial value of delta L equals to 1 and the final value equals 1.
I agree with the initial value, but not with the final one. What are the two distances to the speakers at the final position?
 
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  • #5
mfb said:
I agree with the initial value, but not with the final one. What are the two distances to the speakers at the final position?

Sorry, I meant 3
The vertical distance between the two sources.
 
  • #6
Right, that allows to find how many times you get destructive interference. But the answer is not 4.
 
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  • #7
mfb said:
Right, that allows to find how many times you get destructive interference. But the answer is not 4.

I think that it is 3
Am I right??
 
  • #9
mfb said:
Why 3?
Oh , sorry
delta L will be (3-1) =2
So the numer is two.
I think I'm right now .
 
  • #10
Looks right.
 
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1. What is destructive interference?

Destructive interference occurs when two or more sound waves meet and cancel each other out, resulting in a decrease in amplitude or volume.

2. How do points of destructive interference form?

Points of destructive interference are formed when sound waves with opposite phases meet and combine, causing them to cancel each other out.

3. What causes destructive interference to occur?

Destructive interference is caused by the superposition of two or more sound waves with opposite phases. This means that the peaks of one wave align with the troughs of the other, resulting in cancellation.

4. Do all sound waves experience destructive interference?

No, not all sound waves experience destructive interference. It depends on the relative amplitude and phase of the waves. If the waves have the same amplitude and opposite phases, they will experience destructive interference.

5. How can points of destructive interference be used?

Points of destructive interference can be used to reduce or eliminate unwanted noise or echoes in a given space. By strategically placing barriers or objects to cause destructive interference, sound can be effectively controlled and managed in a room or environment.

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