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A bugle is simply a tube of fixed length that behaves as if it werean open organ

ID: 1664205 • Letter: A

Question

A bugle is simply a tube of fixed length that behaves as if it werean open organ pipe. (open at
both ends) A bugler, by adjusting his lips correctly and blowingwith proper air pressure, can
cause a harmonic (usually other than the fundamental) of the aircolumn within the tube to sound
loudly. Standard military tunes like Taps, andReveille require only four musical notes G4
(392 Hz) C5 (523 Hz) E5 (659 Hz) and G5 (784 Hz). Determine thelength of the tube, L,
which will have a sequence of the four consecutive harmonics closeto G4, C5, E5 and G5.

Explanation / Answer

For an open pipe, the fundamental frequency is given by f0 = v/2L v is the speed of sound in air L is the length of the air coloumn The consecutive frequencies are G4 - 392 Hz                                                      C5 - 523 Hz                                                      E5 - 659 Hz and                                                       G5 - 784 Hz The fundamental frequency is given by v/2L = 523 Hz - 392 Hz (344 m/s)/2L = 131 Hz L = 1.31 m