Answer
a) $6366 \ W/m^2$
b) $4.9 \ W/m^2$
Work Step by Step
We use the equation for intensity to find:
a) $ I = \frac{5\times10^{-3}}{\pi\times(5\times10^{-4})^2}=6366 \ W/m^2$
b) $ I = \frac{5\times10^{-3}}{\pi\times(1.8\times10^{-2})^2}=4.9 \ W/m^2$
