Question

A tuning fork of frequency $480Hz$ is used in an experiment for measuring speed of sound $\left(v\right)$ in air by resonance tube method. Resonance is observed to occur at two successive lengths of the air column, $l_1=30cm$ and $l_2=70cm$. Then $v$ is equal to

• A. $384m{s}^{-1}$
• B. $338m{s}^{-1}$
• C. $379m{s}^{-1}$
• D. $332m{s}^{-1}$
  

Answer 1

The correct option is A $384m{s}^{-1}$

Given,

$f=480Hz$
$l_1=30cm$
$l_2=70cm$
The speed of sound $\left(v\right)$ in air by resonance tube method is given by,
$v=2f(l_2-l_1)$
$v=2\times 480\times (70-30)\times {10}^{-2}$
$v=38400\times {10}^{-2}m/s$
$v=384m/s$
Final answer: (c)