Physics - Sound Wave Question with Solution | TestHub

Fundamental frequency of open pipe is given by, $f_{open}=\frac{v}{2l}$.

Fundamental frequency of closed pipe is given by, 

$f_{closed}=\frac{v}{4l}$.

Therefore,

$$\begin{gathered} \frac{f_{open}}{f_{closed}}=\frac{v}{2l}\times \frac{4l}{v} \\ \Rightarrow f_{open}:f_{closed}=2:1 \end{gathered}$$