Question

If a closed organ pipe has the same third harmonic frequency as that of an open organ pipe, then their respective lengths are in the ratio

• A. 1 : 1
• B. 1 : 2
• C. 1 : 4
• D. 3 : 4
• E. 4 : 5

Answer 1

The correct option is B 1 : 2

Third harmonic

$\begin{array}{c}\Rightarrow \frac{3v}{4l_e}=\frac{3v}{2l_o}\\ \Rightarrow \frac{l_c}{l_o}=\frac{2}{4}=\frac{1}{2}\\ Hence,weget\\ =1:2\end{array}$

So, option $B$ is correct answer.