1. The problem statement, all variables and given/known data A plane polarized electromagnetic wave propagates with Erms = 30 V/m. What is the power transmitted to a circular disk of radius r = 2m, if all of the light is absorbed by the disk and S is perpendicular to the disk? 2. Relevant equations There is a passage that goes along with this that states that I =Erms^2/(cμ0), and that I = P/A. u0 = 4 × 10–7 N•s^2/C^2. 3. The attempt at a solution Basically, I plugged in the values of Erms and μ0 into the Intensity equation and then multiplied by A (pi*4) to get 94.2. But the answer key says the answer is 30 and that instead of multiplying by pi*r^2, you multiply by r^2. Please help!