In the figure below, S is a small loudspeaker driven by an audio oscillator with
ID: 1299457 • Letter: I
Question
In the figure below, S is a small loudspeaker driven by an audio oscillator with a frequency that is varied from 1000 Hz to 2000 Hz, and D is a cylindrical pipe with two open ends and a length of 75.0 cm.
(a) At how many frequencies does the sound from the loudspeaker set up resonance in the pipe?
____ frequencies
(b) What is the lowest frequency (of the given range) at which resonance occurs?
____ Hz
(c) What is the second lowest frequency (of the given range) at which resonance occurs?
____ Hz
Explanation / Answer
A. for a tube open with both ends
fn = n*V/2L = n*343/(2*0.75) = n* 228.66
B. we want value of f between 1000 and 2000 Hz
fmin when n = 5
f5 = 5*228.66 = 1143.3 Hz
C. f6 = 6*228.66 = 1371.96 Hz