The capacitance of a parallel plate capacitor is C when the region between the plates has air. This region is now filled with a dielectric slab of dielectric constant k. the capacitor is connected to a cell of emf E, and the slab is taken out
(A) Charge CE (k-1) flows through the cell
(B) Energy E2 C (k-1) is absorbed by the cell.
(C) The energy stored in the capacitor is reduced by E2 C (k-1)
(D) The external agent has to do 1/2 E2 C (K-1) amount of work to take the slab out.
