A very loud train whistle has an acoustic power output of 100 W. If the sound energy spreads out spherically, what is the intensity level in dB at a distance of 89.0 meters from the train? (I0 = 10?12 W/m2)
a. 20.7 dB
b. 70.0 dB
c. 90.0 dB
d. 95.0 dB
e. 207 dB
c
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