A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

What is the potential difference across $2\mu \mathbf{F}$ capacitor in the circuit shown in Fig.

What is the potential difference between points $A$ and $B$ in the circuit shown in Fig.  ?

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

In the given circuit Fig. when switch $S$ has been closed then charge on capacitor $A$ and $B$ respectively are 

If $64$ identical spheres of charge $q$ and capacitance $C$ each are combined to form a large sphere. The charge and capacitance of the large sphere is