Question

Sound waves from a tuning fork A reach a point P by two separate paths ABP and ACP. When ACP is greater than ABP by 11.5cm, there is silence at P. When the difference is 23cm, the sound becomes loudest at P and when 34.5cm, there is silence again and so on. Calaulate the minimum frequency of the fork if the velocity of sound is taken to be 331.2m/s.

• A. 0.23m, 1440 Hz
• B. 0.46m, 1200 Hz
• C. 0.23m, 1200 Hz
• D. 0.46m, 1440 Hz

Answer 1

The correct option is A 0.23m, 1440 Hz

$\frac{\lambda }{2}=11.5cmor\lambda =23or0.23m$
$f=\frac{v}{\lambda }=\frac{331.2}{0.23}=1440Hz$