Question

Determine the first three standing wave frequencies of a 25.0-cm-long open pipe. Assume the speed of sound in air is 340 m/s. Do the same for a 25.0-cm-long closed pipe.

Answer 1

Formula for open-pipe:
f = nv / (2L)

Formula for closed-pipe:
f = (2n-1)v / (4L)

where
n = harmonic number
v = speed
L = length of pipe

Just substitute the given values to these equations for n = 3.
Units in Hz

Answer 2

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