Sound Level: a Howler Monkey Is the Loudest Land Animal

Multiple Choice

Sound level: A howler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 5.0 km. Assume the acoustic output of a howler to be uniform in all directions and that the threshold of hearing is 1.0 × 10^-12 W/m². The acoustic power emitted by the howler is closest to

A) 0.31 mW.
B) 0.11 mW.
C) 1.1 mW.
D) 3.2 mW.
E) 11 mW.