flux density problem

[jlmac2001]

I have no ideal how to do this problem. Can someone explain it to me? What formula would i use?

An isotropic quasimonochromatic point source radiates at a rate of 100 W. What is the flux density at a distance of 1 m? What are the amplitudes of the E and B fields at that point?

[arcnets]

"Isotropic" means that the emitted power is distributed uniformly over a circular shell. In this case, of radius 1m.
"Quasimonochromatic" means, you may use a harmonic (sinus) wave. Just look up how E and B in such a wave depend on intensity. Key word: Poynting vector.