Given

Electric field with equation

Explanation:

We know that in an electromagnetic wave, the electric and magnetic field magnitudes are related as,

Where c is the speed of the wave, and they are perpendicular to each other, therefore their dot products must be zero, hence the equation for magnetic field will be

Also, since they both oscillate in only one plane i.e. z =0, the electromagnetic wave also oscillates in one direction and therefore the wave is plane polarized. However, the wave is circularly polarized only when, the fields oscillate in a circular fashion, which is not the case here.