Chapter 14 - Sound - Learning Path Questions and Exercises - Exercises - Page 524: 20

a). $8.84\times10^{-3}W/m^{2}$ b). $2.21\times10^{-3}W/m^{2}$

a). $I=\frac{P}{4\times pi \times R^{2}}=\frac{1 W}{4\times pi \times(3m)^{2}}=8.84\times10^{-3}W/m^{2}$ b). $I=\frac{P}{4\times pi \times R^{2}}=\frac{1 W}{4\times pi \times(6m)^{2}}=2.21\times10^{-3}W/m^{2}$