Field of NoThingness - spl BiNal

Two capacitors of capacitance $4 \mu F$ and $12 \mu F$ respectively are connected in series and the combination is connected momentarily across a $200\; V$ battery. The charged capacitors are now isolated and connected in parallel, similar charged plates being connected together. Calculate the common potential.

Two capacitors of capacitances $4\mu F$ and $6\mu F$ respectively are joined in series with a battery of emf $60\; V$. The connections are broken and the like terminals of the capacitors are then joined. Find the final charge on each capacitor.

A parallel plate air capacitor has a capacitance of $10^{-9} \; F$. What potential difference is required for a charge of $5 * 10^{-5}\;C$ ? What is the total energy stored in it?

Two capacitors of capacitances 4μF and 12μF respectively, are connected in series. The combination is then connected momentarily across a 200V battery. Find the charge and potential difference across each capacitor.

Two capacitors of capacitances 5μF and 15μF respectively are connected in series with a battery of 220V . Find the charge and potential across each capacitor.