1. The problem statement, all variables and given/known data ok, for one of the prioblems I'm given the equations of an electric field: Ex(z,t) = E0sin(kz-wt) Ey(z,t) = E0cos(kz-wt) for a circularly polarized plane wave of light traveling in the z direction. I have to show the magnetic field, energy density, and Poynting vector for this wave. 2. Relevant equations the energy density is u = .5 [eE2 + B2/u] the Poynting vector is S = (E x B)/u 3. The attempt at a solution I believe I can just plug in the values of E and B directly in the two equations above; however, I am having a tough time finding out what B is. In my textbook it says the general formula is b(z, t) = (k x E)/c, but I dont know how to compute this cross product. any advice?