Question

In a resonance tube, the first resonance with a tuning fork occurs $16cm$ and second at $49cm$. If the velocity of second is $330m/s$, frequency of tuning fork is:

• A. $500Hz$
• B. $300Hz$
• C. $330Hz$
• D. $165Hz$

Answer 1

The correct option is A $500Hz$

For closed pipe

$l_1=\frac{v}{4n}$ and $l_2=\frac{3v}{4n}$

$v=2n(l_2-l_1)$

$n=\frac{v}{2(l_2-l_1)}$

$n=\frac{330}{2(0.49-0.16)}$

$n=500Hz$