Question

The fundamental frequency of a closed organ pipe is same as the first overtone frequency of the open pipe. The length of open pipe is 50 cm. The length of closed pipe is

• A. 25 cm
• B. 100 cm
• C. 200 cm
• D. 12.5 cm

Answer 1

The correct option is D 12.5 cm

$f_{0\left(open\right)}=\frac{330}{2l}=330Hz$
$f_1=2\times 330=660Hz$
$f_{0\left(closed\right)}=\frac{330}{4l}=660$

or $8l=1m$ that is, $l=12.5cm$