by Guest » Fri Aug 26, 2005 8:50 pm
You can't quite do that as watts are power and joules are energy. A joule is a watt*second.
1 mW/cm^2 = 1 x 10^(-3) W/ 1 x 10^(-4) m^2 = 10 W/m^2
You will then have to look at how many seconds of exposure to get to J/m^2.