A parallel-plate capacitor is filled with a delectric meterial having resistivity`(rho)`and dielectric constant K.The capcitor is charged and disconnected from the charging source. The capacitor is slowly discharged through the dielectric.Show that the time constant of the discharge is independent of all gepmetrical parameters like the plate area or separation between the plates. Find this time constant.

Explanation

Equation of discharging capacitor
` q_0 e^(-2t/rc) `
` = (K epsilon_0 AV/d) (e^(-t/rhoK epsilon_0))`
` r = rhoK epsilon_0` Time constant is rhoK `epsilon_0` is independent of plate area or separation
between the plate.