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deeprony7
A closed pipe and an open pipe have their first overtones identical in frequency. their lengths are in the ratio?
You should mention that sound waves are generated in identical conditions i.e the speed of sound is same in the two experiments. In that case the ratio is 2v/2L1 : 3v/4L2 = 4L2 : 3L1 .
In a closed pipe the fundamental is at L = 1/4 wavelength and the first overtone is at L = 3/4 wavelength (3rd harmonic). In an open pipe the fundamental is at L = 1/2 wavelength and the first overtone is L = 1 wavelength (2nd harmonic). So the length of the closed pipe is 3/4 the length of the open pipe.