Question

State the laws of resistance.

Answer 1

Laws of resistance :

1. If the temperature and other physical variables stay constant, the resistance of a conductor is exactly proportional to its length. It means that $R\propto l$, i.e., if the length rises, the resistance increases as well, and if the length reduces, the resistance lowers as well.
2. When all other variables are constant, the resistance of a conductor is inversely proportional to the area of a cross-section i.e. $R\propto \frac{1}{A}$
3. $R$ is determined by the type of the conductor's substance. It implies that if we take equal lengths of wires made of copper, aluminum, and iron with the same cross-sectional area, their resistance will differ since they are made of various materials.