1.
The electric field part of an electromagnetic wave in a medium is represented by: Ex=0E_x = 0, Ey=2.5E_y = 2.5 N/C cos[(2×106 rad/s)t(π×102 rad/m)x]\cos[(2 \times 10^6 \text{ rad/s})t - (\pi \times 10^{-2} \text{ rad/m})x], Ez=0E_z = 0. The wave is: