Q. In a resonance tube the first resonance with a tuning fork occurs at $16\ cm$ and second at $49\ cm.$ If the velocity of sound is $330\ m/s,$ the frequency of tuning fork is
A) 500
B) 300
C) 330
D) 165
Explanation
(a) For closed pipe $l_{1} = \frac{v}{4n};l_{2} = \frac{3v}{4n} \Rightarrow v = 2n(l_{2} - l_{1})$
$\Rightarrow n = \frac{v}{2(l_{2} - l_{1})} = \frac{330}{2 \times (0.49 - 0.16)} = 500\ Hz$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.