ABSTRACT
Thus primed, let’s reconsider the situation corresponding to the [infinitely] long straight wire carrying electric current I. In the analysis undertaken in Chapter 30, we chose a circular path of radius a in a plane perpendicular to the wire for the computation of the magnetic circulation. The electric current through the flat disk bounded by the path is I, as is the current through any sort of “windsock” path like the one shown in Figure 32.1. It is possible to prove1 that Ampe`re’s Law holds for any [continuous, open, non-self-intersecting] surface, as long as the Amperian path is its only boundary.
