Two parallel plate condensers of capacity of $20 \mathrm{\mu F} \mathrm{and} 30 \mathrm{\mu F}$ are charged to the potentials of $30 \mathrm{V}$ and $20 \mathrm{V}$, respectively. If likely charged plates are connected together, then the common potential difference will be

Two condensers, one of capacity $C$ and the other of capacity $\frac{C}{2}$ are connected to a $V \mathrm{volt}$ battery as shown. The work done in charging both the condensers fully is,

The energy required to charge a parallel plate condenser of plate separation $d$ and plate area of cross-section $A$ such that the uniform electric field between the plates is $E$, is 

A $40 \mu \mathrm{F}$ capacitor in a defibrillator is charged to $3000 \mathrm{V}$. The energy stored in the capacitor is sent through the patient during a pulse of duration $2 \mathrm{ms}$. The power delivered to the patient is