Question

How to calculate resistance value from resistivity?

Answer 1

To calculate the resistance R of a wire, we need to know three things:

its length – the longer the wire, the greater its resistance

its cross-sectional area A – the greater the area, the less its resistance

the resistivity of the material r – the greater the resistivity, the greater its resistance.

resistance = resistivity × length / area

This equation defines resistivity. We can rearrange it to get a formula for resistivity:

resistivity = resistance × area / length