Here's the question: An electromagnetic wave is traveling through vacuum. Its electric field vector is given by E= E_0 sin(kx-wt)y_hat where "y hat" is the unit vector in the y direction. What is the Poynting vector S(x,t), that is, the power per unit area associated with the electromagnetic wave described in the problem introduction? Please express in terms of all or some of the folowing variables: E_0, B_0, k,x,w,t, mu_0 and the unit vectors x_hat, y_hat and z_hat. I've already tried (E_0 * B_0)/ mu_0....it didnt work, i think they want the answer in more depth! Any help is appreciated!!