Halliday 2 Cap 18 - P18 022

Transcript

22. (a) The intensity is given by I = P/4πr2 when the source is “point-like.” Therefore, at r = 3.00 m, I= 1.00 × 10−6 W = 8.84 × 10−9 W/m2 . 4π(3.00 m)2 (b) The sound level there is
8.84 × 10−9 W/m2 β = 10 log 1.00 × 10−12 W/m2  = 39.5 dB .