Homework Help: Oscillations in a closed pipe

1. Jan 24, 2004

nina

Why cant closed pipes produce even numbered harmonics? I have been given an explaination, but it isnt very detailed. I'm doing A2 (or just A level) physics, so an explaination suitable for this level would be greatly appreciated!
Thanks.

2. Jan 24, 2004

himanshu121

What explanation have been given to you so far

3. Jan 24, 2004

nina

Just that the 1st overtone has a frequency of 3 times the fundamental frequency, therefore the second harmonic is missing.

Is that all I need to know? It doesnt seem much of an explaination to give in an exam.

4. Jan 24, 2004

himanshu121

yup it not enough Can u calulate the wavelength in terms of L

5. Jan 24, 2004

nina

Yes, I can calculate the wavelength from L. But why is there no second harmonic in a closed pipe?

6. Jan 24, 2004

himanshu121

Coz for Even harmonics u need a arrangement like this
2f, 4f which is clearly not possible

And u never get L = even integer * Wavelength

7. Jan 24, 2004

himanshu121

8. Jan 24, 2004

nina

Thanks! I will look at that more closely. thanks for the link too.

9. Jan 24, 2004

himanshu121

basically it is due to the fact that there is pressure antinode and node at closed and open ends

10. Jan 24, 2004

nina

actually, it makes sense now.
thank you so much. i may just get a good grade in my exam now...

11. Jan 24, 2004

himanshu121

Goodluck for exams