PHY137H5 Lecture Notes - Lecture 1: Nichrome, Capstone Software
Document Summary
The resistivity of different metals is determined by finding the resistance of wires of a known diameter as a function of their length. It is also shown that the resistance of a wire of fixed length is inversely proportional to its cross-sectional area. If a current (i) is flowing through a wire, the voltage drop (v) across a certain length of wire with resistance r is given by ohm"s law: or solving for r gives: In this experiment, you will measure v and i to determine r for various lengths of wire. You will then make a graph of r versus length (l). The resistance of a wire depends on the length of the wire, the cross-sectional area (a), and the resistivity ( ) of the material: V=ir where r/l is the slope of the r versus l graph, and d is the diameter of the wire.
