7.2.4 Factors Affecting the Resistance in a Conductor


The resistance R of a given conductor depends on:
  1. its length l,
  2. its cross-sectional area A
  3. its temperature and
  4. the type of material.

Length


Resistance is directly proportional to the length of the conductor.

Cross Sectional Area


Resistance is inversely proportional to the cross sectional area of the conductor.

Temperature


A conductor with higher temperature has higher resistance.

Material

Difference materials have difference resistivity. The resistance of copper wire is lower than iron wire.

Since resistance is directly proportional to the length and inversely proportional to the cross sectional area of the conductor. If two resistors of same material have same temperature, we can relate the resistance of the two resistors by the following equation.