<em>Passive transport is the movement of molecules and ions across the cell membrane whith no use of energy,</em> it usuale involves a difussion down its concentration gradient (a region where concentration changes) across a membrane, from higher to lower concentrations. Passive transport can happen by simple diffusion, facilitated diffusion, filtration, or osmosis.
I hope you find this information useful and interesting! Good luck!
In this case the coordinate z is multiplied by your wave vector k, so it travels along z. Note that the electric field will be oscillating along the x direction. H and E are perpendicular to the direction of travel in vacuum.
<u />
<u />