Question

An organ pipe 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 ?

• A. 14
• B. 13
• C. 6
• D. 9

Answer 1

Answer: (C)

6

We know that fundamental frequency of closed organ pipe, $f=\frac{V}{4L}$

where, $V=$ velocity of wave and $L=$ length of pipe.

It is given that fundamental frequency, $f=1500Hz$

Maximum frequency a human can hear $=20000Hz$

Equating nth frequency, $f^{\prime }=\frac{(2n+1)V}{4l}$ where $n$ is overtone.

We get $(2n+1)1500=20000$

So, $2n+1$ = $20000/1500$ = $13.33$

As $2n+1$ is an integer, so $2n+1=13$

So, we get $n=6$