(i) The capacitance of capacitor increases to \(\mathrm{K}\) times \(\left(\right.\) since \(\left.C=\left(\mathrm{K} \varepsilon_{0}^{\mathrm{A}}\right) / d \propto \mathrm{K}\right)\)
(ii) The potential difference between the plates becomes \(1 / K\) times.
Reason: \(\mathrm{V}=\mathrm{Q} / \mathrm{C} ; \mathrm{Q}\) same, \(\mathrm{C}\) increases to \(\mathrm{K}\) times; \(\mathrm{V}^{\prime}=\mathrm{V} / \mathrm{K}\)
(iii) As \(E=V / d=\) and \(V\) is decreased; therefore, electric field decreases to \(1 / K\) times. Energy stored by the capacitor, \(U=Q^{2} / 2 C\). As \(Q=\) constant, \(C\) is increased, and so energy stored by capacitor decreases to \(1 /\) K times