Residents of Hawaii are warned of the approach of a tsunami (tidal wave) by sirens mounted on the top of towers. Suppose a siren produces a sound that has an intensity level of 120 dB at a distance of 2.0m.
a) What is the intensity level of 20 of those sirens at the same distance?
b) Treating the siren as a point source of sound, and ignoring reflections and absorption, find the intensity level of one siren heard by an observer at a distance of 12 m.