Path for Ampere's law Plane surface Bulging surface A parallel-plate capacitor with plates of radius R is being charged by the current ic. Recall Ampere's Law B.d-po Although there is no current between the plates, there is a reshuffling of charge q on the surfaces. Maxwell realized that this time dependent charge redistribution acts like a current (aka displacement current Ip). In class, we learned that the electric field magnitude inside a capacitor is E = Q/(A0). where A is the plate area. a) Using ID=dQ/dt, show that the change in the electric field is dE/dt = ID/(60A). In other words, it looks like there is a current ID=AdE/dt inside the capacitor. b) Apply Ampere's Law around a loop of radius r < R inside the capacitor to calculate the interior magnetic field strength B.