The unit of permittivity of free space is

When a $0.75 \mu F$ capacitor is charged to a voltage of $20 \ V$,then the magnitude of charge on each plate is (in $\mu C$)

$A$ capacitor is formed by two concentric spherical shells. The potential of the shell with radius $R_1$ is $V_1$ and the potential of the shell with radius $R_2$ is $V_2$. What is the potential at a point at a distance $x$ from the center? $(R_2 > x > R_1)$

The capacity of a spherical conductor in the $MKS$ system is:

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 unit of electric permittivity is