  We are concerned with the quantitative study of the electric field
perturbation due to the presence of an inhomogeneous conductive rod embedded in
a homogenous conductivity. We sharply quantify the dependence of the perturbed
electric field on the geometry of the conductive rod. In particular, we
accurately characterise the localisation of the gradient field (i.e. the
electric current) near the boundary of the rod where the curvature is
sufficiently large. We develop layer-potential techniques in deriving the
quantitative estimates and the major difficulty comes from the anisotropic
geometry of the rod.The result complements and sharpens several existing
studies in the literature. It also generates an interesting application in EIT
(electrical impedance tomography) in determining the conductive rod by a single
measurement, which is also known as the Calderon's inverse inclusion problem in
the literature.
