An air capacitor is made by using two flat parallel plates, each with area A separated by a distance d. Then a metal slab having thickness a(a(a) What is the capacitance C 0​ of the arrangement without the metal slab?
(b) What is the capacitance C of this arrangement with the metal slab inserted? (Express the capacitance as a multiple of the capacitance C 0 )
(c) Discuss what happens to the capacitance in the limits a>0 and a−d.