The intensity of the sound wave is defined as the ratio between the power of the wave and the area through which the wave passes:
[tex]I= \frac{P}{A} [/tex]
where
I is the intensity
P is the power
A is the area
If we use the data of the problem, [tex]P=8.8 \cdot 10^{-4}W[/tex] and [tex]A=5.0 m^2[/tex], we find the intensity of the sound wave:
[tex]I= \frac{P}{A}= \frac{8.8 \cdot 10^{-4} W}{5.0 m^2}=1.76 \cdot 10^{-4} W/m^2 [/tex]
