Aparallel-plate capacitor is made using two circular plates of radius a, with the bottom plate on the xy plane, centered at the origin. the top plate is located at z = d, with its center on the z axis. charge q is on the top plate; −q is on the bottom plate. dielectric having z-dependent permittivity fills the region between plates. the permittivity is given by ϵ(z) = ϵ0(1 + z2/d2). find (a) d; (b) e; (c) v0; (d) c.