Answer
$P_{mic}=4.48\times10^{-9}W$
Work Step by Step
The power intercepted by the microphone$'P_{mic}'$ can be calculated as follows
$P_{mic}=IA_{mic}$
As $1cm^2=(10^{-2}m)^2$
thus $0.750cm^2=0.750\times10^{-4}m^2$
put the value of $I$ from part $'a'$ in the above equation
$P_{mic}=(5.97\times10^{-5})(0.750\times10^{-4})$
$P_{mic}=4.48\times10^{-9}W$
