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 $C$)

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:

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 $\mu C$)

$A$ solid conducting sphere of radius $R_1$ is surrounded by a hollow conducting sphere of radius $R_2$. The capacitance of this assembly is proportional to ........

Four capacitors,each of $25\,\mu F$,are connected as shown in the figure. The $dc$ voltmeter reads $200\,V$. The charge on each plate of the capacitor is

$A$ sphere of $4\, cm$ radius is suspended within a hollow sphere of $6\, cm$ radius. The inner sphere is charged to a potential of $3\, e.s.u.$ and the outer sphere is earthed. The charge on the inner sphere is.....$e.s.u.$