Question

A cylindrical tube, open at both ends has a fundamental frequency $f$ in air. If the tube is dipped vertically in water so that half of it is dipped, then then the fundamental frequency of air column is now

• A. $f$
• B. $2f$
• C. $f/2$
• D. $3f/4$

Answer 1

The correct option is A $f$

On dipping in water, the tube becomes closed at that end and that too of half the length
So, ${\eta }_0=\frac{v}{2I_0}=f$
and $n_c=\frac{v}{I_c}=\frac{v}{I_0/2}=\frac{v}{2I_0}=f$