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

Two metallic charged spheres whose radii are $20\,cm$ and $10\,cm$ respectively, have each $150\,micro - coulomb$ positive charge. The common potential after they are connected by a conducting wire is

When two isolated conductors $A$ and $B$ are connected by a conducting wire positive  charge will flow from :-

A spherical capacitor consists of two concentric spherical conductors, held in position by suitable insulating supports (Figure). Show that the capacitance of a spherical capacitor is given by

$C=\frac{4 \pi \varepsilon_{0} r_{1} r_{2}}{r_{1}-r_{2}}$

where $r_{1}$ and $r_{2}$ are the radii of outer and inner spheres, respectively.

The distance between the circular plates of a parallel plate condenser $40\,mm$ in diameter, in order to have same capacity as a sphere of radius $1\;metre$ is....$mm$

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.

Assertion $A:$ Two metallic spheres are charged to the same potential. One of them is hollow and another is solid, and both have the same radii. Solid sphere will have lower charge than the hollow one.

Reason $R:$ Capacitance of metallic spheres depend on the radii of spheres.

In the light of the above statements, choose the correct answer from the options given below.