# Homework Help: What is the speed of sound in oxygen? 21.50mastering physics

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1. Jul 26, 2015

1. The problem statement, all variables and given/known data
___ In 1866, the German scientist Adolph Kundt developed a technique for accurately measuring the speed of sound in various gases. A long glass tube, known today as a Kundt's tube, has a vibrating piston at one end and is closed at the other. Very finely ground particles of cork are sprinkled in the bottom of the tube before the piston is inserted. As the vibrating piston is slowly moved forward, there are a few positions that cause the cork particles to collect in small, regularly spaced piles along the bottom. The figure shows an experiment in which the tube is filled with pure oxygen and the piston is driven at 400 Hz.
(Figure 1)
https://session.masteringphysics.com/problemAsset/1383985/3/21.P50.jpg

2. Relevant equations
I think the equation is frequency = mv/(2L) m is number of

3. The attempt at a solution
I think my problem is happening in figuring out m and wether this is a closed-closed open open or open closed column of air.
re- arranging to find v makes (400Hz*2*1.23M)/(?mode) I tried counting spaces between the 6 corks so 5 space 196.8 for some reason when m is three it is the correct answer I'm not sure why 328 m/s worked 3 amount of cork spots decided by two? any thoughts

2. Jul 26, 2015

### ehild

m is the number of what?

which one? is it a node or antinode at the vibrating piston?

3. Jul 27, 2015

### andrevdh

A standing wave forms in the tube.
The cork lies at the position of the nodes.

4. Jul 27, 2015

### SammyS

Staff Emeritus
123cm corresponds to a node separation of 123/3 = 41 (cm) .

Last edited: Jul 27, 2015