Question 469: Waves

Question

A pipe open at both ends has a fundamental frequency $f$ in air. The pipe is now dipped vertically in a water drum to half of its length. The fundamental frequency of the air column is now equal to:

Accepted Answer

Fundamental frequency of open pipe (at both ends) $f=\frac{V}{2 L} \ldots$ (i)
Now immersed in water open pipe behaves as closed pipe.
$$\begin{aligned}
& f^{\prime}=\frac{v}{4\left(\frac{L}{2}ight)}=\frac{v}{2 L} \quad	ext{..... (ii)}\
& f=f^{\prime}
\end{aligned}$$

Answer

$\frac{3 f}{2}$

Answer

$2 f$

Answer

$\frac{f}{2}$

Answer

$f$

Waves

A pipe open at both ends has a fundamental frequency f in air. The pipe is now dipped vertically in a water drum to half of its length. The fundamental frequency of the air column is now equal to:

Choose the correct answer: