u 10. An electromagnetic plane wave has a wavelength of 700 .nm, an average intensity of 1.00k-W/m2, and travels in the -y direction with the E-eld in the +X direction at its maximum value at t = x = O. 3) Find Em from the average intensity S . c) Write down the electric and magnetic field vectors f?(z,t) and (z,t) with appropriate unit vectors, and numbers and units except for z and t. b) Find the frequency (in Hz)