Two condensers of capacities $10\mu F$ and $20\mu F$ have potential differences of 20V and 10V respectively. The total charge is

‘A’ and ‘B’ are two condensers of capacities 2 $\mu F$ and 4$\mu F$ They are charged to potential differences of 12V and 6V respectively. If they are now connected (+ve to +ve), the charge that flows through the connecting wire is :

Two capacitors of capacities 3$\mu$F and 6$\mu F$ are connected in series and connected to 120V. The potential differences across 3$\mu$F is $V_0$ and the charge here is $q_0$. We have :

A)$q_0=40\mu C$     B) $V_0=60V$

C)$V_0=80V$        D)$q_0=240\mu C$