$A$ uniform electric field of magnitude $100 \ V/m$ in space is directed along the line $y = 3 + x$. Find the potential difference between point $A(3, 1)$ and $B(1, 3)$ in Volts.

If a unit positive charge is taken from one point to another over an equipotential surface,then

The figure shows three points $A, B$ and $C$ in a uniform electric field $(\overrightarrow{E})$. The line $AB$ is perpendicular to $BC$ and $BC$ is parallel to $\overrightarrow{E}$. If $V_A, V_B$ and $V_C$ are the potentials at $A, B$ and $C$ respectively,then the correct option is

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

Describe schematically the equipotential surfaces corresponding to
$(a)$ a constant electric field in the $z$-direction,
$(b)$ a field that uniformly increases in magnitude but remains in a constant (say,$z$) direction,
$(c)$ a single positive charge at the origin,and
$(d)$ a uniform grid consisting of long equally spaced parallel charged wires in a plane.

Equipotential surfaces are shown in the figure. Then the electric field strength will be