A pan flute uses a set of open cylindrical pipes to produce musical notes

PHYSICS · Multi-part · CBSE · Physics · Waves · Waves

Problem

A pan flute uses a set of open cylindrical pipes to produce musical notes. One particular pipe of length L0=0.30 mL_0 = 0.30\,\text{m} is tuned to its fundamental frequency. A player wishes to raise the pitch of this same physical pipe by a musical interval of a perfect fifth (frequency ratio 3:23:2) without shortening the pipe. They propose partially sealing the bottom of the pipe with a removable plug of wax so that the pipe behaves as closed at a point located a distance xx above the original bottom end. End corrections may be neglected and the speed of sound is taken as vv. (1) Part 1: (a) Write expressions for the fundamental frequencies of the pipe when it is (i) completely open at both ends and (ii) effectively closed at a distance xx from the bottom. (2) Part 2: (b) Using the requirement that the closed configuration produce a note one perfect fifth above the open-pipe note, derive an equation relating xx to the original length L0L_0. (3) Part 3: (c) Solve the equation from part (b) to find the numerical value of xx for L0=0.30 mL_0 = 0.30\,\text{m}. (4) Part 4: (d) Discuss qualitatively how sensitive the resulting pitch is to small errors in the placement of the wax plug, citing your reasoning.

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