You can use the formula in the previous section for light, sound, and radiation to determine the intensity 5 m away from a point source radiating at a rate of 10 W.
$I\=\frac{P}{4\mathrm{pi;}{r}^{2}}$
$I\=\frac{10\mathrm{W}}{4\mathrm{pi;}{\left(5\mathrm{m}\right)}^{2}}$
$I\=0.03\mathrm{W}sol;{\mathrm{m}}^{2}$.
Therefore, the intensity 5.0 m away from a point source radiating at a rate of 10 W is 0.03 $\mathrm{W}\/{\mathrm{m}}^{2}\.$