Question

A small omnidirectional stereo speaker produces waves in all directions that have an intensity of 8.00 at a distance of 4.00 from the speaker.

At what rate does this speaker produce energy?

What is the intensity of this sound 9.50 from the speaker?

What is the total amount of energy received each second by the walls (including windows and doors) of the room in which this speaker is located?

Answer 1

given that

    radius r = 4.00 m

      intensity I = 8.00 W/m^2

a) total power = power/ Area ( 4πr²)

                        = 8.00 w/m^2 ( 4π ( 4.00 m)²

                         =1607.68 W

b) I = total power/ 4πr²

        = 8.00 W/m² ( 4.00 m/ 9.5 m)²

         = 1.418 W/m²

c)   E = total power x time

            = 1607 . 68 W x 1s

            = 1607.68 J