## Essential University Physics: Volume 1 (3rd Edition)

a) $6366 \ W/m^2$ b) $4.9 \ W/m^2$
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) $I = \frac{5\times10^{-3}}{\pi\times(1.8\times10^{-2})^2}=4.9 \ W/m^2$