The electric potential at a perpendicular distance r from a long straight wire of cross-sectional radius a is given by
V(r) = – K In(r/a)
Where K is a constant. Calculate the electric field as a function of distance. Hence, using Gauss’s theorem, determine the charge q per unit length of the wire.
A second identical wire, carrying charge-q per unit length, is placed parallel to the first at a distance d from it. Calculate the potential difference between the wire, assuming that d >> a.