Required equation
Intensity \(I=\frac{\text { Power }}{\text { Area }}=\frac{P}{4 \pi r^{2}}\)
where \(4 \pi r ^{2}=\) Area of a sphere (since the wave comes out like a spherical wavefront)
Power \(=0.05 \times 4 \pi \times 3^{2}=5.65 W\)