A noisy grinding machine in a factory which produces a sound intensity of 1.00 x 10⁻⁵ W/m².
Calculate (a) the decibel level of this machine and (b) the new intensity level when a second, identical machine is added to the factory. (c) A certain number of additional such machines are put into operation alongside these two machines. When all the machines are running at the same time the decibel level is 77.0 db. Find the sound intensity.