A source of sound of frequency $600\text{ Hz}$ is placed inside water. The speed of sound in water is…
A source of sound of frequency $600\text{ Hz}$ is placed inside water. The speed of sound in water is $1500\text{ ms}^{-1}$ and in air is $300\text{ ms}^{-1}$. The frequency of sound recorded by an observer who is standing in air is
$200\text{ Hz}$
$3000\text{ Hz}$
$120\text{ Hz}$
$600\text{ Hz}$
Solution
As here,
(i) Due to compressions and rarefactions, density of the medium (air) changes. At compressed regions, density is maximum and at rarefactions, density is minimum.
(ii) As density is changing, so Boyle's law is not obeyed.
(iii) Bulk modulus remains same.
(iv) The time of compression and rarefaction is too small, i.e. we can assume adiabatic process and hence, no transfer of heat.