Physics - Sound Wave Question with Solution | TestHub

The average power per unit area that is incident perpendicular to the direction of propagation is called the intensity. Intensity of sound $I=\frac{P}{4\pi r^2}$ or, $I\propto \frac{1}{r^2}$ or, $\frac{I_1}{I_2}={\left(\frac{r_2}{r_1}\right)}^2$ here, $r_1=2\mathrm{m},r_2=3\mathrm{m}$ Substituting the values, we have $\frac{I_1}{I_2}={\left(\frac{3}{2}\right)}^2=\frac{9}{4}$