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nina
Jan24-04, 12:28 PM
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.

himanshu121
Jan24-04, 12:32 PM
What explanation have been given to you so far

nina
Jan24-04, 12:37 PM
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.

Thanks for your help...

himanshu121
Jan24-04, 12:44 PM
yup it not enough Can u calulate the wavelength in terms of L

nina
Jan24-04, 12:45 PM
Yes, I can calculate the wavelength from L. But why is there no second harmonic in a closed pipe?

himanshu121
Jan24-04, 12:58 PM
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

himanshu121
Jan24-04, 01:02 PM
http://www.phys.unsw.edu.au/music/pipes.html

nina
Jan24-04, 01:03 PM
Thanks! I will look at that more closely. thanks for the link too.[:)]

himanshu121
Jan24-04, 01:09 PM
basically it is due to the fact that there is pressure antinode and node at closed and open ends

nina
Jan24-04, 01:14 PM
actually, it makes sense now.
thank you so much. i may just get a good grade in my exam now...
[:)]

himanshu121
Jan24-04, 01:19 PM
Goodluck for exams[:))]