Chp 17, #25?

Question

A source emits sound waves isotropically. The intensity of the waves 3.37 m from the source is 2.39 × 10-4 W/m2. Assuming that the energy of the waves is conserved, find the power of the source.

Answer 1

The surface area of a sphere of radius 3.37 m is

4 π r^2

Multiply that area by the given intensity ( power per square meters ) to get the power at the source.

Answer 2

I= P/ (4πr^2)
P=2.39*10^-4*4π3.37^2
P=0.034W