An electric field `E_(0) = 3xx10^(4) Vm^(-1)` is established between the plates `0.05m` apart, of a parallel plate capacitor. After removing the charging battery, an uncharged metal plate of thickness `t = 0.1 m` is inserted between capacitor plates. Find the `p.d.` across the capacitor, (i) before (ii) after the introduction of plates (iii) what would be the `p.d` if a dielectric slab `(K = 2)` were introduced of place of metal plate.