A Microphone in the Ocean Is Sensitive to the Sounds

Short Answer

A microphone in the ocean is sensitive to the sounds emitted by porpoises. To produce a usable signal, sound waves striking the microphone must have an intensity of 1.02 × 10−¹¹ W/m². If porpoises emit sounds with a power of 0.049 9 W, how far away can a porpoise be and still be heard? Disregard absorption of sound waves by the water.