How are radio waves produced?

Sea water at frequency $v = 4 \times 10^8\, Hz$ has permittivity $\epsilon \approx 80\epsilon_0$,permeability $\mu = \mu_0$ and resistivity $\rho = 0.25\,\Omega m$. Imagine a parallel plate capacitor immersed in sea water and driven by an alternating voltage source $V(t) = V_0 \sin(2\pi vt)$. What fraction of the conduction current density is the displacement current density?

Write the meaning of the equation $i = i_c + i_d$.

In the charging of a capacitor,what is the contradiction in Ampere's circuital law?

$A$ circular parallel plate capacitor of radius $R$ and spacing $d$ is being charged by a constant current $I_D$. Find the magnetic field between the plates at a distance $r$ from the axis,where $r > R$.

An infinitely long thin wire carrying a uniform linear static charge density $\lambda$ is placed along the $z-$axis. The wire is set into motion along its length with a uniform velocity $\vec{V} = v\hat{k}$. Calculate the Poynting vector $\vec{S} = \frac{1}{\mu_0}(\vec{E} \times \vec{B})$.