The variation of potential with distance R from a fixed point is as s…

the electric field at R = 5 m is $\left(\frac{4}{5}\right)$ V-m^-1

the electric field at R = 5 m is $\left(\frac{4}{5}\right)$ V-m⁺¹

the potential at R = 5m is +2.5 V-m^–1 is continuous and a decreasing function of distance.

the segment AB corresponds to an equipotent surface.