9.17 The ratio J/Ja (conduction current density to displacement current density) is very impor- tant at high frequencies. Calculate the ratio at 1 GHz for: (a) distilled water (μ = (b) seawater (u (c) limestone (μ = μ&= &=818, σ = 2 × 103 S/m) 818, σ = 25 S/m) Mo, 8580, σ = 2 × 101 S/m)