posted by BILL on .
At a recent rock concert, a dB meter registered 118 dB when placed 1.60 m in front of a loudspeaker on the stage.
(a) What was the power output of the speaker, assuming a hemispherical radiation of the sound and neglecting absorption in the air?
Answer in W
(b) How far away would the intensity level be a somewhat reasonable 85 dB?
Answer in m