Question

The distance between a maximum and the adjacent minimum displacement is 5 cm. If the speed of the sound wave is 330 m/s, then the frequency of the sound wave is equal to

• A. 3300 Hz
• B. 6600 Hz
• C. 1650 Hz
• D. 825 Hz

Answer 1

The correct option is C 1650 Hz



Let the wavelength of the wave be $\lambda .$
From the figure:
$OC=\lambda \Rightarrow AB=\frac{\lambda }{4}\Rightarrow \lambda =4\times AB=20cm=0.2m(\because AB=5cm)$
Speed of sound wave, $v=330m/s$
Let the frequency of sound wave be f.
Now,$f=\frac{v}{\lambda }\Rightarrow f=\frac{330}{0.2}(\because \text{Speed of sound, v=330 m/s})\Rightarrow f=1650Hz$

Hence, the correct answer is option (c).