The capacitance of a spherical condenser is $1\,\mu F$. If the spacing between the two spheres is $1\,mm$,then the radius of the outer sphere is

The radii of a spherical capacitor are $0.5 \ m$ and $0.6 \ m$. If the space between them is filled with a dielectric medium of dielectric constant $6$,what will be the capacitance of the capacitor?

$1000$ small water drops,each of capacitance $C$,join together to form one large spherical drop. The capacitance of the bigger sphere is ......... $C$.

$A$ 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).

Eight drops of mercury of equal radii and possessing equal charge combine to form a big drop. If the capacity of each drop is $C$,then the capacity of the big drop is: (in $C$)

Capacitance of an isolated conducting sphere of radius $R_{1}$ becomes $n$ times when it is enclosed by a concentric conducting sphere of radius $R_{2}$ connected to earth. The ratio of their radii $\left(\frac{R_{2}}{R_{1}}\right)$ is: