Question

If fundamental frequency of an open pipe is $f_0$. Its fundamental frequency when it is half-filled with water is :

• A. $f_0$
• B. $\frac{\lambda }{4}$
• C. $2f_0$
• D. none of these

Answer 1

The correct option is A $f_0$

When the pipe is half filled with water , it becomes a closed pipe with length

$\frac{l}{2}=\frac{\lambda }{4}$

$\lambda =2l$

same wavelength existed in open pipe . Therefore , frequency remains unchanged .