Question

Sea water at frequency ν = 4 × 10⁸ Hz has permittivity ε ≈ 80 ε_o, permeability μ ≈ μ_o and resistivity ρ = 0.25 Ω–m. Imagine a parallel plate capacitor immersed in sea water and driven by an alternating voltage source V(t) = V_osin(2πνt). What fraction of the conduction current density is the displacement current density?

Answer 1

Let the distance between the plates be d. Then the electric field E=Vo/d sin(2πvt). The conduction current density is given by the Ohm’s law = E.

The displacement current density is given as