Imagine a harmonic plane electromagnetic wave traveling in the z-direction in a homogeneous isotropic dielectric. If the wave, whose amplitude is Eo, has a magnitude of zero at t = 0 and z = 0, (a) show that its energy density is given by %3D u(t) = eEj sin² k(z – vt) (b) Find an expression for the irradiance of the wave.

Imagine a harmonic plane electromagnetic wave traveling in the z-direction in a homogeneous isotropic dielectric. If the wave, whose amplitude is Eo, has a magnitude of zero at t = 0 and z = 0, (a) show that its energy density is given by %3D u(t) = eEj sin² k(z – vt) (b) Find an expression for the irradiance of the wave.