3.9 Problems
Section 3.1
Section 3.2
Section 3.3
Section 3.4
Section 3.5
Section 3.6

Type of tube 
Fundamental 
300, 400, 500, 600 Hz ? 


600, 1000, 1400, 1800 Hz ? 


100, 200, 400, 800 Hz ? 


120, 220, 320, 420 Hz ? 



Extra frequency 
Type of tube 
Fundamental 
375, 625, 700, 875, 1125 Hz ? 



300, 450, 750, 900, 1050 Hz ? 



450, 675, 900, 1125, 1300 Hz ? 



800, 960, 1600, 2240, 2880 Hz ? 



Closed Tube 
Frequency 
Wavelength 
1 
771 Hz 

2 
1468 Hz 

3 
2184 Hz 

The speed of sound really must be the same in all cases, so assume that it is 347.5 m/sec. Calculate the wavelength of each mode. Now, make a CAREFUL sketch of the modes on the following graphs using the calculated wavelength (place the nodes and antinodes first):
What you can see is that the speaker is not a perfectly closed end, so the node is not exactly at the end of the tube. This is a big error for the fundamental. By the third node, things look O.K.
Section 3.7
Section 3.8