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` then the fundamental frequency of the open pipe. The fundamental frequency of the open pipe is

Options

A. 150 Hz
B. 200 Hz
C. 250 Hz
D. 300 Hz

Answer

B

Explanation

For open pipe, `n_(o) = V/(2L) ` and for the third harmonic of the closed pipe `n_(c) = 3 (V/(4L)) = 3/2 (V/(2L)) = 3/2 n_(o) `
But `n_(c) = n_(o) + 100`
` :. n_(o) + 100 = 3/2 n_(o) " " :. 1/2 n_(o) = 100 " or " n = 200` Hz