The electric field Ex is along the x-axis,
and varies sinusoidally with z, at a given time The
magnetic field By is along the y-axis, and again varies
sinusoidally with z The electric and magnetic fields Ex
and By are perpendicular to each
other, and to the direction z of
propagation We can write Ex and
By as follows:
Ex= E0 sin (kz–wt)
[8