A metal tube that is closed at one end has an adjustable piston that can slide to vary the length of the enclosed air column. When the length is set to Lc=0.60m, the tube is driven so that it resonates at its third harmonic.
A second tube made of the same material is open at both ends and has negligible end corrections.
(a) Compute the frequency produced by the closed tube under the stated conditions. Take the speed of sound as v=340ms−1.
(b) Determine the length Lo that the open tube must have so that its resonance frequency matches the frequency found in part (a). State which harmonic of the open tube is involved.
(c) If the open tube were instead to be tuned to its fundamental frequency while keeping the length found in part (b), what frequency would it produce? Comment on whether this new note is higher or lower than the common resonance found in parts (a) and (b).