If $27$ identical charged conducting spheres each of capacitance $10 \mu F$ combine to form a big sphere,then the capacitance of the big sphere is: (in $\mu F$)

Eight drops of mercury, each of same radius and same charge, combine to form a bigger drop. The ratio of the capacitance of the bigger drop to that of each smaller drop is: (in $ : 1$)

The capacity of a conductor does not depend upon:

$A$ conductor is connected to a battery of $5\, V$. It acquires a charge of $50\ \mu C$. Calculate the capacitance of the conductor in $\mu F$.

In a spherical condenser, the radius of the outer sphere is $R$. The difference in the radii of the outer and inner sphere is $x$. Its capacity is proportional to:

The radii of the inner and outer spheres of a spherical capacitor are $9\,cm$ and $10\,cm$ respectively. If the dielectric constant of the medium between the two spheres is $6$ and the charge on the inner sphere is $18 \times 10^{-9}\,C$,calculate the potential of the inner sphere,given that the outer sphere is earthed.