[UPSC CSE 2026] Electromagnetic Theory (Q294, 10M)

In a homogeneous non-conducting region where \mu_r = 1, find \epsilon_r and \omega, if \begin{align*} \vec{E} &= 30\pi e^{j[\omega t - (4/3)y]} \vec{a}_z \quad (\text{V/m}) \ \vec{H} &= 1\cdot 0 e^{j[\omega t - (4/3)y]} \vec{a}_x \quad (\text{A/m}) \end{align*}