Question

The frequency of a closed pipe is $f_1$ if it vibrates with two nodes and is $f_2$ if it vibrates with three nodes. If the difference between the frequencies $f_1$ and $f_2$ is 200 Hz, then the length of the pipe is (Speed of sound in air $=340\,ms^{-1}$)

• A. $75\text{ cm}$
• B. $65\text{ cm}$
• C. $85\text{ cm}$
• D. $55\text{ cm}$

Hint:

For a closed pipe: \[ f=\frac{nv}{4L} \] where \(n=1,3,5,\ldots\). Only odd harmonics are present.

Answer 1

The Correct Option is B