I solved the first question and got the right answer, but I just can't seem to get the correct answer for the second part.
(a) An AM radio transmitter broadcasts 52.0 kW of power uniformly in all directions. Assuming all of the radio waves that strike the ground are completely absorbed, and that there is no absorption by the atmosphere or other objects, what is the intensity 31.0 km away? (Hint: Half the power will be spread over the area of a hemisphere.)
Answer: 4.31×10-6 W/m^2
(b) What is the maximum electric field strength at this distance? (in mV/m)
I solved and got an equation for Emax, but I still don't get the right answer when I plug in my intensity above.
Emax=sqrt(2*I/(3e8*8.85e-12)
Any help would be appreciated!!