Consider the parallel-plate capacitor of Problem 6.30, but this time the charged dielectric exists only between z = 0 and z = b, where b < d. Free space fills the region b < z < d. Both plates are at ground potential. By solving Laplace’s and Poisson’s equations, find

(a) V(z) for 0 < z < d;

(b) the electric field intensity for 0 < z < d.