Problem 4.183

At a distance \(r_{0}=20.0 \mathrm{~m}\) from a point isotropic source of sound the loudness level \(L_{0}=30.0 \mathrm{~dB}\). Neglecting the damping of the sound wave, find: (a) the loudness level at a distance \(r=10.0 \mathrm{~m}\) from the source; (b) the distance from the source at which the sound is not heard.