$A$ point charge is placed at point $P$ as shown in the figure. $A$ hollow conducting sphere is placed in the electric field produced by it. If $V_A$,$V_B$,and $V_C$ are the potentials at points $A$,$B$,and $C$ respectively,then:

Two point charges $-Q$ and $+Q / \sqrt{3}$ are placed in the $xy$-plane at the origin $(0,0)$ and a point $(2,0)$,respectively,as shown in the figure. This results in an equipotential circle of radius $R$ and potential $V = 0$ in the $xy$-plane with its center at $(b, 0)$. All lengths are measured in meters.
$(1)$ The value of $R$ is. . . . meter.
$(2)$ The value of $b$ is. . . . . .meter.

Assertion: Two equipotential surfaces cannot cut each other.
Reason: Two equipotential surfaces are parallel to each other.

What is the angle between an equipotential surface and electric lines of force (in $^{\circ}$)?

The angle between the electric lines of force and the equipotential surface is (in $^{\circ}$)

In an electric field due to charge $Q$,a charge $q$ moves from point $A$ to $B$ along an arc of a circle centered at $Q$,as shown in the figure. The work done is ($\varepsilon_0=$ permittivity of free space).