The electric potential at a point certain distance from a point charge is $600 \mathrm{V}$ and the electric field is $200 \mathrm{N} {\mathrm{C}}^{-1}$. Which of the following statements will be true?

There is a fixed positive charge $Q$ at $O$, and $A$ and $B$ are points equidistant from $O$. A positive charge $+q$ is taken slowly by an external agent from $A$ to $B$ along the line $AC$ and then along the line $CB$.

$S$ is a solid neutral conducting sphere. A point charge $q$ of $1\times {10}^{-6} \mathrm{C}$ is placed at a point $A$. $C$ is the centre of the sphere, and $AB$ is a tangent. $BC=3 \mathrm{m}$ and $AB=4 \mathrm{m}$,

Figure shows two conducting thin concentric shells of radii $r$ and $3r.$ The outer shell carries charge $q$ and the inner shell is neutral. The amount of charge that flows from the inner shell to the earth after the key $K$ is closed is equal to ${\left(\frac{1}{n}\right)}^{\mathrm{th}}$ of the charge on the outer shell. What is the value of $n?$