Question

A sound wave with a power of 8.8 × 10–4 W leaves a speaker and passes through section A, which has an area of 5.0 m2. What is the intensity of sound in this area? (Intensity = I = ) 1.8 × 10–4 W/m2 1.8 × 10–6 W/m2 1.6 × 10–4 W/m2 1.6 × 10–6 W/m2

Answer 1

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:
$I= \frac{P}{A}$
where
I is the intensity
P is the power
A is the area

If we use the data of the problem, $P=8.8 \cdot 10^{-4}W$ and $A=5.0 m^2$, we find the intensity of the sound wave:
$I= \frac{P}{A}= \frac{8.8 \cdot 10^{-4} W}{5.0 m^2}=1.76 \cdot 10^{-4} W/m^2$