Capacitor

A parallel combination of two capacitors of capacities '\(2 ~\mathrm{C}\)' and '\(\mathrm{C}\)' is connected across \(5 \mathrm{~V}\) battery. When they are fully charged, the charges and energies stored in them be '\(\mathrm{Q}_1\)', '\(Q_2\)' and '\(E_1\)', '\(E_2\)' respectively. Then \(\frac{E_1-E_2}{Q_1-Q_2}\) in \(\mathrm{J} / \mathrm{C}\) is (capacity is in Farad, charge in Coulomb and energy in J)