Imagine a conductor wire spacially defined by 4 points, in order,?
From a theoretical point of view, we can answer this using Ohms law: V = I R Between C and D, if V = then either I = or R = . Between A and B, if V = 10 V then either: R is infinite, and no current flows, or R is finite, and a current I = V / R flows. Now, to get from A to B, that current also has to flow between C and D. This means we cant have I = in this section, so the resistance between C and D must be zero. Are any of these theoretical possibilities actually feasible in a practical setup? We can certainly have infinite resistance between A and C, or between D and B (or both). Were then free to make the voltages whatever we like. We probably wouldnt call it a conductor wire in that case, though. We probably cant make the resistance between C and D actually zero (unless theyre the same point) but we can make the resistance here very much lower than the resistance elsewhere in the wire, so that the 10 V is mostly dropped over A-C and D-B. Then wed have V = almost between C and D, and the current flow would be determined by the resistances between A-C and D-B.