Question

1(a) What length should a tube closed at one end have on a day when the speed of the sound is 340 m/s, if its fundamental frequency is to be 128 Hz (C below middle C)?

Answer 1

For a tube closed at one end the length of the tube is 1/4 λ,

Note: a closed tube at one end has node-antinode-node-antinode-etc

The fundamental is node-antinode for λ/4

In this case λ = 4 L

f = V / λ = V / (4 L)

L = V ( 4 f) = 340 m/s / (4 * 128 / s) = .664 m for the fundamental length