# Sea water at frequency ν = 4 × 10^8 Hz has permittivity ε ≈ 80 εo, permeability μ ≈ μo and resistivity ρ = 0.25 Ω–m.

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Sea water at frequency ν = 4 × 108 Hz has permittivity ε ≈ 80 εo, permeability μ ≈ μo 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) = Vosin(2πνt). What fraction of the conduction current density is the displacement current density?

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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