Question

 An open pipe is suddenly closed at one end with the result that the frequency of third harmonic of the closed pipe is found to be higher by 100 Hz than the fundamental frequency of the open pipe. Find the fundamental frequency of the open pipe.

Answer 1

For the open pipe, the fundamental frequency is ν₁ = v/2l , where v is the velocity of sound in air and l = Length of the pipe. For the third harmonic of the closed pipe,