An open pie is suddenly closed at one end with the result that the frequency of third harmonic of the closed pipe is found to be heigth by `100 H_(Z)` than the fundamental frequency of the open pipe. The fundamental frequency of the open pipe is
(a) `200 H_(Z)` (b) `300 H_(Z)` (c ) `240 H_(Z)` (d) `480 H_(Z)`

Options

A. 100 Hz
B. 300 Hz
C. 150 Hz
D. 200 Hz

Answer

D

Explanation

`n_(3) = 5V//4l` (second overtone of closed pipe )
`n_(2) = 2V//2l` (for first overtone of open pipe )
But `(5V//4l) - (2V//2l) = 100, V//2l = 200 Hz`.
Fundamental frequency of open pipe = 200 Hz