Answer
(a) $1.56\times 10^{12}W$
(b) $4.95\times 10^{17}W/m^2$
(c) $1.37\times 10^{10}V/m$
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:
$P=\frac{0.350}{225\times 10^{-15}}$
$P=1.56\times 10^{12}W$
(b) We can find the average intensity as
$I_{avg}=\frac{P}{A}$
We plug in the known values to obtain:
$I_{avg}=\frac{1.56\times 10^{12}}{\pi (1.00\times 10^{-3})^2}$
$I=4.95\times 10^{17}W/m^2$
(c) We know that
$E_{rms}=\sqrt{\frac{I_{avg}}{c\epsilon_{\circ}}}$
We plug in the known values to obtain:
$E_{rms}=\sqrt{\frac{4.95\times 10^{17}}{(3.00\times 10^8)(8.85\times 10^{-12})}}$
$E_{rms}=1.37\times 10^{10}V/m$
