Eight drops of mercury of equal radii combine to form a big drop. The capacitance of a bigger drop as compared to each smaller drop is (in $\times$)

$A$ cylindrical capacitor has two co-axial cylinders of length $15 \; cm$ and radii $1.5 \; cm$ and $1.4 \; cm$. The outer cylinder is earthed and the inner cylinder is given a charge of $3.5 \; \mu C$. Determine the capacitance of the system and the potential of the inner cylinder. Neglect end effects (i.e.,bending of field lines at the ends).

Consider a charged cylindrical capacitor. The magnitude of the electric field $\vec{E}$ in its annular region:

Which one of the following is the correct dimensional formula for the capacitance in $F$? $M, L, T$ and $C$ stand for units of mass,length,time,and charge respectively.

The capacity of an isolated sphere is increased $n$ times when it is enclosed by an earthed concentric sphere. The ratio of their radii is

If the circumference of a sphere is $2 \ m$,find the capacitance of the sphere in water in $pF$. (Take dielectric constant of water $K = 80$)