Discussion Forum



1)

A pipe open at both ensa has a fundamental frequency f in air. The pipe is dipped vertically in the water, so that half of it is in water, The fundamental frequency of the air column is now


A) $\frac{f}{2}$

B) $\frac{3f}{4}$

C) $2f$

D) $f$

Answer:

Option D

Explanation:

The fundamental frequency  of open pipe 

                          $f=\frac{v}{2l}$

  Now, after half-filled with water it becomes a closed pipe of length l/2

The fundamental frequency of this closed pipe.

                $f'=\frac{v}{4(\frac{l}{2})}$

                                   = $\frac{v}{2l}=f$