Question

A typical adult ear has a surface area of 1.92 × 10-3 m2. the sound intensity during a normal conversation is about 2.13 × 10-6 w/m2 at the listener's ear. assume that the sound strikes the surface of the ear perpendicularly. how much power is intercepted by the ear?

Answer 1

The sound intensity is the ratio between the power of the wave and the surface:

`I= (P)/(A)`
where
I is the intensity
P is the power
A is the area

In our problem, the sound intensity is
`I=2.13 \cdot 10^(-6) W/m^2`, and the surface area of the ear is
`A=1.92 \cdot 10^(-3) m^2`, so if we re-arrange the previous equation and we use these data we can find the sound power:

`P=IA=(2.13 \cdot 10^(-6) W/m^2)(1.92 \cdot 10^(-3) m^2)=4.09 \cdot 10^(-9) W`