8) A tiny vibrating source sends waves uniformly in all directions. An area of 3.25 cm2 on a sphere of radius 2.50 m from the source receives energy at a rate of 4.20 J/s.
(a) What is the intensity of the waves at 2.50 m from the source and at 10.0 m from the source?
(b) At what rate is energy leaving the vibrating source of the waves?

Question

8)  A tiny vibrating source sends waves uniformly in all directions. An area of 3.25 cm2 on a sphere of radius 2.50 m from the source receives energy at a rate of 4.20 J/s.
(a) What is the intensity of the waves at 2.50 m from the source and at 10.0 m from the source?
(b) At what rate is energy leaving the vibrating source of the waves?

experimentx · Answer

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Intensity = energy received per unit area per unit time.
and it remains conserved.
a) change the area 3.25 to meter square, you will have intensity
Energy remains conserved, so Intensity at 10m will be (2.5/10)^2 times intensity at 2.5