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

$1000$ small water drops,each of capacitance $C$,join together to form one large spherical drop. The capacitance of the bigger sphere is ......... $C$.

$A$ spherical capacitor consists of two concentric spherical conductors. Find the capacitance of the spherical capacitor if the outer radius is $2 R$ and the inner radius is $R$.

Consider a charged cylindrical capacitor. The magnitude of the electric field $\vec{E}$ in its annular region:

What is a capacitor? Explain capacitance and give its $SI$ unit.

$A$ spherical capacitor is made of two spherical shells of radii $a$ and $b$ $(b > a)$. The medium between the shells is air. What is the difference between the capacitances when the outer shell is grounded and when the inner shell is grounded?