Question

The fundamental frequency of sound produced in an open pipe of length \(L_1\) is same as the frequency of the 3rd harmonic of the sound produced in the closed pipe of length \(L_2\). Then the ratio of \(\frac{L_1}{L_2}\) is:

• A. \(\frac{L_1}{L_2} = \frac{3}{1}\)
• B. \(\frac{L_1}{L_2} = \frac{1}{3}\)
• C. \(\frac{L_1}{L_2} = \frac{2}{3}\)
• D. \(\frac{L_1}{L_2} = \frac{3}{2}\)

Hint:

Open pipe fundamental: \(f = \frac{v}{2L}\); Closed pipe odd harmonics: \(f = \frac{nv}{4L}\) where \(n=1,3,5,\dots\).

Answer 1

The Correct Option is C