If the circumference of a sphere is $3 \ m$,then the capacitance of the sphere in water is (dielectric constant of water = $80$) (in $pF$)

$A$ capacitor of unknown capacitance $C$ is connected across a battery of $V$ volt. The charge stored in it becomes $Q$ coulomb. When the potential across the capacitor is reduced by $V^{\prime}$ volt,the charge stored in it becomes $Q^{\prime}$ coulomb. The capacitance $C$ 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 of capacitance $C$ is charged to a potential $V$. The flux of the electric field through a closed surface enclosing the positive plate of the capacitor 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

The Earth is assumed to be a charged conducting sphere having volume $V$ and surface area $A$. The capacitance of the Earth in free space is ($\epsilon_{0} =$ permittivity of free space).