A plane eelctromagnetic wave travelling along $+z$ – direction, has its electric field given by
$\mathrm{E}_{x}=2 \cos \left({ }^{*} t\right)$ and $\mathrm{E}_{y}=2 \cos \left({ }^{*} t+90^{\circ}\right)$.
The wave is
- linearly polarised
- right circularly polarised
- left circularly polarised
- elliptically polarised