# 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.

Thanks for your help...

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