The howler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 8.9 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. A juvenile howler monkey has an acoustic output of 63 µW. What is the ratio of the acoustic intensity produced by the juvenile howler to the reference intensity I₀, at a distance of 210 m? A) 110 B) 230 C) 76 D) 170 E) 300

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Quizplus · Accepted Answer

The intensity (I) at a distance (r) is given by I = P / (4πr²), where P is the power. For the juvenile howler, P = 63 µW = 63 × 10⁻⁶ W. At 210 m, I = 63 × 10⁻⁶ / (4π(210)²). The reference intensity I₀ is 1.0 × 10⁻¹² W/m². The ratio I/I₀ is approximately 110.

The Howler Monkey Is the Loudest Land Animal And, Under