In the circuit, 1&2 are joined for long time. After disconnecting 1&2, 2&3 are connected. The charge on the capacitor when the current in the inductor (ideal) decreases by 3A is [nearly]

When 1&2 are closed for long time imax=51=5 amp  through inductor .When 2&3 are joined, by law of conservation of energy 12Limax2=12Li2+q22C122×10−3×25=122×10−3×4+q22×4×10−3q=168×10−3≈  13×10−3C