The angle between electric field lines and an equipotential surface is .........$^o$.

Equipotential surfaces at a very large distance from a collection of charges whose total sum is not zero are approximately . . . . . . .

As per the diagram,a point charge $+q$ is placed at the origin $O$. The work done in taking another point charge $-Q$ from point $A$ [coordinates $(0, a)$] to point $B$ [coordinates $(a, 0)$] along the straight path $AB$ is:

$A$ uniform electric field is directed along the $Y$-axis. Consider point $A$ as the origin $(0,0) \text{ m}$. The coordinates of point $B$ are $(0,2) \text{ m}$. The coordinates of point $C$ are $(2,0) \text{ m}$. If the electric potentials at points $A, B,$ and $C$ are $V_A, V_B,$ and $V_C$ respectively,which of the following options is correct?

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

Three infinitely long wires with linear charge density $\lambda$ are placed along the $x$-axis,$y$-axis,and $z$-axis respectively. Which of the following denotes an equipotential surface?