Resonance in Closed Air Coloumn

[SRForum]

Hello,

My teacher and the textbook seem to be conflicting with each other, and I would like to know who's right. The image on the left was scanned streight out my my textbook, saying that the third resonance is 5/4 lamda. On the right, is an edited version of the textbook image,showing what my teacher had showed me to display the third resonance in an air coloum. He calims that it's 1 lamda. Who's right? or are they both right? Thanks in advance for any help!
http://img428.imageshack.us/img428/9123/resonance8hc.png

 

[SRForum]

bump?

 

[jollygood]

1/2 lambda or 1/2 wave length is the distance between two succesive nodes or anti-nodes(crests).

so your textbooks shows

1 full wave length + 1/4 of a wave length

so 1 + 1/4 = 5/4 wave length ( or 5/4 lambda)

so it is correct.

your teacher's diagram;

1 full wave length + 3/4 of a wave length = 7/5 wave lenghts (7/4 lambda)

which is actually the 4th resonance. NOT the third!