Suppose we have a cylindrical resistor, with resistance given by $R=\rho\cdot l/(\pi r^2)$ Let $d$ be the distance between two points in the interior of the resistor and let $r\gg d\gg l$. Ie. it is approximately a 2D-surface (a rather thin disk). What is the resistance between these two points? Let $r,l\gg d$, (ie a 3D volume), is the resistance $0$ ? ---------------------------------------------- Update: An alternate exposition of the problem goes as follows: A voltage difference is applied between two points a distance d apart, inside a material with resistivity $\rho$, and the current is measured, the proportionality constant V/I is called R. The material is a cylinder of height $l$ and radius $r$, and the two points are situated close to the center, we can write R as a function of $l$, $r$ and $d$, $R(l,r,d)$, for small $d$. The questions are then: What is (lim r->inf (lim l->inf ($R(l,r,d)$)))? What is (lim r->inf (lim l->0 ($R(l,r,d)$)))?