Basic Electrical and Electronics Engineering Principles

3.1. Resistance and resistivity

          The resistance of an electrical conductor depends on
four factors, these being:

(a) the length of the conductor,
(b) the cross-sectional area of the conductor, 

(c) the type of material 

(d) the temperature of the material.
Resistance, R, is directly proportional to length, l, of a
conductor, i.e. R ∝ l. Thus, for example, if the length of a piece of wire is doubled, then the resistance is doubled.