Question

The low-frequency speaker of a stereo set has a surface area of and produces 1W of acoustical power. What is the intensity at the speaker

Answer 1

I =
`(1)/(4\pi \ r^2)`

we see the intensity decreases with the inverse of the distance squared

Step-by-step explanation:

Intensity is defined as power per unit area,

I = P / A

in this case we have that the sound is emitted in a spherical form therefore the area is

A = 4 pi r2

therefore the intensity is

I =
`(1)/(4\pi \ r^2)`

as we see the intensity decreases with the inverse of the distance squared