Question

A tuning fork of frequency $440Hz$ resonates with a tube closed at one of length. $1.8cm$ and diameter $5cm$ in the fundamental mode. The velocity of sound in air is?

• A. $336m{s}^{-1}$
• B. $343m{s}^{-1}$
• C. $300m{s}^{-1}$
• D. $350m{s}^{-1}$

Answer 1

The correct option is B $343m{s}^{-1}$

In the fundamental mode of vibration,
$(l+0.3D)=\frac{\lambda }{4}=\frac{\nu }{4\nu }$

$\therefore \nu =4\nu (l+0.3D)=4\times 440(0.18+0.3\times 0.5)$

$\nu =343m{s}^{-1}$