no impurities, the intrinsic resistance must vanish although the contract resistance is high. An electrical device having a resistance of 5 ohms would be represented as. In this context, the ultimate conductor would be a very thin one-dimensional wire that has no defects to inhibit resistance-free currents. For an even more accurate resistance measurement, you could set up a bridge circuit, like the basic Wheatstone bridge shown here: Image source: All About Circuits vol. A third variable that is known to affect the resistance to charge flow is the material that a wire is made. While the electric potential difference established between the two terminals encourages the movement of charge, it is resistance that discourages. If it is smoking refrain from using the power and wait until the wire has cooled down. The vanishing of the intrinsic resistance agrees with the simple notion that the current-carrying electrons should move freely if there are no obstacles. It will be powered by a power pack in which I will change the voltage to get different results. Modern dry cell construction uses a steel can connected to the positive (raised) contact.
Physics : Finding the resistance of a wire?
Home experiment - How to measure resistance of a piece of wire?
Intuition tells us that a wire without defects should have zero resistance. In either case, erich Maria Remarque - All Quiet on the Western Front different wires should be made of the same material. Students should be encouraged to adjust the voltage to keep currents small with every set of readings. This discharges the cell rapidly and can make it explode. I, chapter.9, this arrangement allows you to exclude any additional sources of resistance along the current path, such as the contacts between the voltage source terminals and the wire, from the resistance measurement.
Physics Resistance of wires