A parallel-plate capacitor has plates of area 10 cm² separated by a 0.10-mm layer of glass insulation with resistivity r = 1.2x10¹³ Ω m and dielectric constant k = 5.6. Because of the finite resistivity, charge leaks through the insulation.
(a) How can such a leaky capacitor be represented in a circuit diagram?
(b) Find the time constant for this capacitor to discharge through its insulation, and show that it depends only on the properties of the insulating material and not on its dimensions.