Time-averaging this quantity and dividing by the s
Time-averaging this quantity and dividing by the speed of light yields the radiation pressure.  Integrating this quantity over a volume gives the total energy (*) flow through that volume, and its direction is along the direction of wave propagation. For 10 points— identify this quantity which represents the amount of energy in an electromagnetic wave and is given by the cross product of the electric and magnetic fields.
Time-averaging this quantity and dividing by the speed of light yields the radiation pressure.  
Poynting vector