The energy stored in the above capacitor is
The energy stored in the capacitor = 12\;\frac{1}{2}21 q2C\;\frac{q^{2}}{C}Cq2
Where C = 2F, q = 3C
= 12\;\frac{1}{2}21 322\;\frac{3^{2}}{2}232 = 94\;\frac{9}{4}49 = 2.25J
