$A$ metallic sphere has a charge of $10\,\mu C$. $A$ unit negative charge is brought from $A$ to $B$,both $100\,cm$ away from the sphere,with $A$ being east of it and $B$ being west of it. The net work done is........$joule$.

The figure shows three points $A, B$ and $C$ in a region of uniform electric field $E$. The line $A B$ is perpendicular and $B C$ is parallel to the field lines. Then,which of the following holds good? ($V_{A}, V_{B}$ and $V_{C}$ represent the electric potential at points $A, B$ and $C$,respectively)

Prove that a closed equipotential surface with no charge within itself must enclose an equipotential volume.

$A$ hollow conducting sphere is placed in an electric field produced by a point charge placed at $P$ as shown in the figure. Let $V_A, V_B, V_C$ be the potentials at points $A, B,$ and $C$ respectively. Then:

Positive and negative point charges of equal magnitude are kept at $(0, 0, a/2)$ and $(0, 0, -a/2)$,respectively. The work done by the electric field when another positive point charge is moved from $(-a, 0, 0)$ to $(0, a, 0)$ is

The figure shows lines of constant potential in a region where an electric field is present. The electric field at point $B$ is............