The dielectric strength of air at $NTP$ is $3 \times 10^6 \, V/m$. The maximum charge that can be given to a spherical conductor of radius $3 \, m$ is:

The capacitance of a spherical capacitor is $1 \mu F$. If the spacing between the two spheres is $1 \text{ mm}$,the radius of the outer sphere is

$A$ 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).

The radius of a metallic sphere if its capacitance is $1/9\,F$,is

The respective radii of the two spheres of a spherical condenser are $12 \; cm$ and $9 \; cm$. The dielectric constant of the medium between them is $6$. The capacity of the condenser will be

For the shown situation,in the steady state condition,the ratio of the charge stored in the first capacitor to the charge stored in the $n^{th}$ capacitor is: