A slab of material of dielectric constant K has the same area as the plates of a parallel plate capacitor but has thickness 3d/4, where d is the distance between plates. How is the capacitors changed when the slab is inserted between the plates?
C=Aϵ0d
C′=Aϵ0d−t+tk
Put t=3d4 ;
C′=4k3+k.Aϵ0d
C′=4k3+k.C