In steady state, the capacitors are fully charged and act as open circuit, so the equivalent circuit in steady state would be as shown:- ∴ Steady State current is I=2+412=2A ∴ Potential difference across AB is V=2×4=8V ∴ Sum of potential difference across 2μF and 4μF capacitors is 8V . As these are in series, so charges on them would be same. Let q be the charge on them, then:-
From KVL, 2q+4q=8⇒q=332μC