Exercise: I'm suppose to prove that e1 = e2 e1 = ∫E*dl e2 = ∫dB/dt*dS where S is the surface encircled by the conture c. c is a box with with a length (in x axis) and b height (in y axis). for an electromagnetic wave: E = E0*sin(kx - wt) (in y axis) I'm ASSUMING this means that B = B0*sin(kx - wt) (in z axis) Pathetic Attempt: e1 calculated on the outside of c becomes b*E(x + a,t) - b*E(x,t) = E0*sin(kx + ka - wt) + E0*sin(kx - wt) This expression is confusing and doesn't lead to any simplification at all. e2 = ∫dB/dt*dS dB/dt = B0*-w*cos(kx - wt) Now heres the tricky part, how do I integrate this infinitly thing vector over a surface? The wave has no thickness, shouldn't the integral be zero?!