At a rock concert, the sound intensity 1.0 m in front of the bank of loudspeakers is 0.10 W/m2. A fan is 30 m from the loudspeakers. His eardrums
eardrums have a diameter of 8.4 mm.How much energy is transferred to each eardrum in one second?

Question

At a rock concert, the sound intensity 1.0 m in front of the bank of loudspeakers is 0.10 W/m2. A fan is 30 m from the loudspeakers. His eardrums
 eardrums have a diameter of 8.4 mm.How much energy is transferred to each eardrum in one second?

anonymous · Answer

Assuming a 1/r^2 fall-off of sound intensity with distance r, the intensity at 30m
will be (1/30^2) x 0.1 W/m2 = 1/900 x 0.1 W/m2. Calculate the area of each circular eardrum in square meters and multiply by the intensity there.