Q. A pipe open at both ends produces a note of frequency $f_{1}.$ When the pipe is kept with $\frac{3}{4}th$ of its length in water, it produced a note of frequency $f_{2}.$ The ratio $\frac{f_{1}}{f_{2}}$ is
A) $\frac{3}{4}$
B) $\frac{4}{3}$
C) $\frac{1}{2}$
D) $2$
Explanation
(c) For open pipe $f_{1} = \frac{v}{2l}$ and for closed pipe
$f_{2} = \frac{v}{4 \times \left( \frac{l}{4} \right)} = \frac{v}{l} = 2f_{1} \Rightarrow \frac{f_{1}}{f_{2}} = \frac{1}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.