You need to insert a metal slab between two plates of a parallel-plate capacitor. The plates are a distance d apart, and a battery maintains a constant potential difference Vbatt between them. In order to avoid dielectric breakdown, the electric field in any region cannot exceed 4Vbatt/d. (a) What is the maximum thickness of the metal slab that can be used without causing dielectric breakdown?(b) If this maximum thickness is used, does the insertion of the metal slab affect the amount of charge stored in the capacitor?