Answer
a) $P=250KW$
b) $I=4.41\times 10^{11}W/m^3$
c) $P=138mW$
Work Step by Step
(a) We can find the required power as
$P=\frac{E}{\Delta t}$
We plug in the known values to obtain:
$P=\frac{2.50\times 10^{-3}}{10.0\times 10^{-9}}$
$P=250KW$
(b) We can find the average intensity as
$I=\frac{P}{A}$
We plug in the known values to obtain:
$I=\frac{250\times 10^3}{\pi (0.425\times 10^{-3})}$
$I=4.41\times 10^{11}W/m^3$
(c) We know that
$P=Ef$
We plug in the known values to obtain:
$P=(2.50\times 10^{-3})(55)$
$P=138mW$
