What are the resonant wavelengths?

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Homework Help Overview

The discussion revolves around the resonant wavelengths of a pipe that is closed at one end and open at the other. Participants are exploring the relationship between the length of the pipe and the standing waves that can form within it, specifically focusing on the implications of having a node at the closed end and an antinode at the open end.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to identify the resonant wavelengths based on the length of the pipe and are questioning the use of the speed of light versus the speed of sound in air. There is also discussion about the relevance of nodes and antinodes in understanding resonance.

Discussion Status

The discussion is active with participants providing insights and questioning the assumptions made regarding the speed of sound and the characteristics of standing waves in pipes. Some participants are seeking clarification on the concepts of resonance and the specific conditions needed for the problem.

Contextual Notes

There is mention of a specific length for the pipe (L=5), but there are uncertainties regarding the concepts covered in class, particularly about the differences between closed and open pipes and the application of end corrections in resonance.

physics(L)10
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Homework Statement


Consider pipe of length L. The pipe is closed at one end and open at the other allowing a standing wave where a node exists at the closed end and a max exists at the open end.
a) what are the resonant wavelengths?
b) If L=5, what is the lowest frequency?


Homework Equations


f= c/L where c=speed of light, L=pipe length, f=frequency


The Attempt at a Solution



I think I got it right, I'm just looking for some confirmation and any other insight you may have for me.

a) L since it says the pipe length is L, it can't go any longer then that.

b) f=C/ L = 3*10^8/5= 0.6*10^8 Hz=60 Mega Hz
 
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physics(L)10 said:

Homework Statement


Consider pipe of length L. The pipe is closed at one end and open at the other allowing a standing wave where a node exists at the closed end and a max exists at the open end.
a) what are the resonant wavelengths?
b) If L=5, what is the lowest frequency?


Homework Equations


f= c/L where c=speed of light, L=pipe length, f=frequency


The Attempt at a Solution



I think I got it right, I'm just looking for some confirmation and any other insight you may have for me.

a) L since it says the pipe length is L, it can't go any longer then that.

b) f=C/ L = 3*10^8/5= 0.6*10^8 Hz=60 Mega Hz

Are you guys studying sound waves in pipes? If so, you don't need c, you need the speed of sound in air... Also did you discuss pipe lengths and how the nodes and antinodes produced by inteference cause resonance in the pipes if they are the proper length? You perhaps discussed tuning forks vibrating air in a pipe of some length? Anything familiar in what I have written?
 
Last edited:
pgardn said:
Are you guys studying sound waves in pipes? If so you don't need c, you need the speed of sound in air... Also did you discuss pipe lengths and how the nodes and antinodes produced by inteference cause resonance in the pipes if they are the proper length? You perhaps discussed tuning forks vibrating air in a pipe of some length? Anything familiar in what I have written?

We are just touching on basics of different waves, sound included. Yes we did touch a little on the nodes. No, we did not discuss tuning forks in a pipe.
 
physics(L)10 said:
We are just touching on basics of different waves, sound included. Yes we did touch a little on the nodes. No, we did not discuss tuning forks in a pipe.

Did you discuss the difference between closed at one end and open and both end pipes and sound? Because if you did not, its not easy to make sense of what you need to put in for L, the length of the pipe.
 
This might help. Read resonance of a air in a tube... I doubt you guys are using the end correction part... There are some nice diagrams that display the standing waves produced along with the nodes and antinodes in both types of tubes.

http://en.wikipedia.org/wiki/Acoustic_resonance

Im off for fishing...
 
I don't believe we did, but if you say that it wouldn't make sense if we didn't, then why would we be assigned this question? And it says that L=5 in part b.
 

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