Johnny measures a sound level of 120 dB at a distance x5m fr

Johnny measures a sound level of 120 dB at a distance x=5m from a source. The power arriving on his eardrum of surface S=.05cm^2 is

Solution

Intenisty of sound level is given by

B=10Log(I/I_o)

120=10Log(I/10^-12)

I=1 W/m²

Power on the ear drum is

P=I*S=1*(0.05*10^-4)

P=0.05*10^-4 Watts