A closed pipe is suddenly opened and changed to an open pipe osf same lenghth .The fundamental frequency of the resulting open pipe is less than that of `3^(rd)` harmonic of the earlier closed pipe by 55 Hz .THEN the value of fundamental frequency of the closed pipe is,

Options

A. 165 Hz
B. 110Hz
C. 55Hz
D. 229Hz

Answer

C

Explanation

`n_1=(3y)/(4l) and n_2= y/(2l)=55 (Given)`
` therefore n_1-n
_2=(3y)/(4l)-y/(2l)`
` implies (6yl-4y)/(8t^2)=55`
`implies (2y)/(8l)=55`
`implies (y)/(4l)=55Hz`