Answer
The intensity is given by $I=P / 4 \pi r^{2}$ when the source is "point-like." Therefore, at
$r=3.00 \mathrm{m},$
$$
I=\frac{1.00 \times 10^{-6} \mathrm{W}}{4 \pi(3.00 \mathrm{m})^{2}}=8.84 \times 10^{-9} \mathrm{W} / \mathrm{m}^{2}
$$
Work Step by Step
The intensity is given by $I=P / 4 \pi r^{2}$ when the source is "point-like." Therefore, at
$r=3.00 \mathrm{m},$
$$
I=\frac{1.00 \times 10^{-6} \mathrm{W}}{4 \pi(3.00 \mathrm{m})^{2}}=8.84 \times 10^{-9} \mathrm{W} / \mathrm{m}^{2}
$$
