A sound source emits 20.0 W of acoustical power spread equally in all directions. The threshold of hearing is 1.0 × 10-12 W/m2. What is the sound intensity level 30.0 m from the source?
A) 92.5 dB
B) 81.5 dB
C) 1.77 × 10-3 dB
D) 1.77 × 10-3 W
E) -27.5 dB
A
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