Final answer:
The electromagnetic wave described by the given electric field components is elliptically polarized, with the electric field vector rotating in the yz-plane and tracing out an ellipse due to a phase difference.
Step-by-step explanation:
The polarization of an electromagnetic wave describes the orientation of the electric field vector as the wave propagates. In the given electromagnetic wave, the electric field has components in the y and z directions, with the equations Ey = 8cos(6t + 2x + π/4) and Ez = -8cos(6t + 2x). The presence of both y and z components with a phase difference (indicated by the π/4 term) suggests that this wave is elliptically polarized. If the coefficients of the cosine terms were equal and the phase difference was π/2, the wave would be circularly polarized, but this is not the case here.
The electric field vector rotates in the yz-plane as the wave travels, tracing out an ellipse due to the phase difference; thus, the polarization is elliptical. This type of polarization can occur when two linearly polarized waves of the same frequency and different amplitudes combine with a phase difference that is not an integer multiple of π/2.