Question

Distance between successive compression and rarefaction in a sound wave is $1\text{m}$. If the velocity of sound is $360{\text{ms}}^{-1}$, find the frequency of sound wave.

• A. $180\text{Hz}$
• B. $160\text{Hz}$
• C. $150\text{Hz}$
• D. $120\text{Hz}$

Answer 1

The correct option is A $180\text{Hz}$

We know that velocity of sound wave is given by,
$v=\lambda f$
where $\lambda$ is wavelength and $f$ is frequency.

Now, as we can see in the diagram below, the distance between successive compression and rarefaction is $\frac{\lambda }{2}$. It is given that this distance is $1\text{m}$

$\Rightarrow \frac{\lambda }{2}=1\Rightarrow \lambda =2\text{m}$


So frequency, $f=\frac{v}{\lambda }$

$\Rightarrow f=\frac{360}{2}$

$\Rightarrow f=180\text{Hz}$