JEE Main 2022 · 28 Jun · Shift 2, Physics question 56

A capacitor $C_1$ of capacitance 5 $\mu$F is charged to a potential of 30 V using a battery. The battery is then removed and the charged capacitor is connected to an uncharged capacitor $C_2$ of capacitance 10 $\mu$F as shown in figure. When the switch is closed charge flows between the capacitors. At equilibrium, the charge on the capacitor $C_2$ is ______ $\mu$C.