[UPSC CSE 2026] Electromagnetic Theory (Q295, 15M)

The magnetic field $H$ of an electromagnetic wave travels in the $-a_z$ direction in free space with a phase shift constant of $30\text{ rad/m}$ and an amplitude of $\left(\frac{1}{3\pi}\right)\text{ A/m}$ . If the field has the direction $-a_y$ when $t = 0$ and $z = 0$ , write the suitable expressions for $E$ and $H$ . Determine the frequency and wavelength of the wave.