Matthiessen’s rule

Matthiessen’s rule states that the total electrical resistance of a metal is the sum of its different sources of resistance, mainly caused by imperfections and vibrations within the material. For example, resistance from impurities, defects, or thermal vibrations adds up independently. If you increase temperature, resistance from vibrations rises, and if the metal has impurities, that also adds to resistance. These effects are additive, meaning the total resistance is just the sum of individual contributions, helping us understand and predict how metals conduct electricity under various conditions.