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

Answer 1

Answer: (C)

$384m{s}^{-1}$

$v=2f(l_2-l_1)$
$v=2\times 480\times (70-30)\times {10}^{-2}$
$v=960\times 40\times {10}^{-2}$
$v=38400\times {10}^{-2}m/s$
$v=384m/s$