Work done is calculated by change * potential difference 
 in equation it means: W = Q * V 
 since the 2 terminals have now dq charge and (V) potential difference 
 small work done (dW) = V dq 
 total work done W = V Q = 12 * 3.3*10^5 = 3.96 *10^6 Joules which is approximately 4 mega joules