An organ pipe is closed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is

Options

A. 14
B. 13
C. 6
D. 9

Answer

C

Explanation

Critical hearing frequency for a person in 20,000 Hz. If a closed pipe vibration in `N^(th)` mode then frequency of vibration
`n = ((2N - 1)v)/(4l) = (2N - 1)n_(1)`
(where `n_(1)` = fundamental frequency of vibration)
Hence `20000 = (2N - 1) xx 500 impliesN = 7.1 approx 7`
Also, in closed pipe we use
Numuber of over tones = (No. of mode of vibration) -1 = 7-1 = 6.