The electric field vector of a wave is given as \overrightarrow{ E }= E _{0} e ^{ j (\omega t+3 x-4 y)} \frac{8 \vec{a}_{x}+6 \vec{a}_{y}+5 \vec{a}_{z}}{\sqrt{125}} V / m
Its frequency is 10 GHz
(i) Investigate if this wave is a plane wave,
(ii) Determine its propagation constant, and
(iii) Calculate the phase velocity in y-direction