Seawater at frequency $v=4 \times 10^8 \mathrm{~Hz}$ has permittivity $\varepsilon=80 \varepsilon_{0}$, permeability $\mu=\mu_{0}$ and resistivity $\rho=$ $0.25 \Omega \mathrm{m}$. Imagine a parallel plate capacitor immersed in seawater and driven by an alternating voltage source $V(t)=V_{0} \sin (2 \pi v t) .$ What fraction of the conduction current density is the displacement current density?

The separation between the plates of the capacitor is given as $V(t)=V_{0} \sin (2 \pi v t)$

Ohm’s law for the conduction of current density is given as $\mathrm{J}_{0}{ }^{\mathrm{c}}=\mathrm{V}_{0} / \mathrm{pd}$

The displacement current density is known as $\mathrm{J}_{0}{ }^{\mathrm{d}}=2 \pi \mathrm{v} \varepsilon \mathrm{V}_{0} / \mathrm{d}$

The fraction of the conduction of current density and the displacement density $=\mathrm{J}_{0} \mathrm{~d} / \mathrm{J}_{0} \mathrm{c}=4 / \mathrm{g}$