The resistivity of a wire is a measure of how strongly the material opposes the flow of electric current. It is given by the formula:
R = ρ * (L / A)
Where:
- R is the resistance of the wire.
- ρ (rho) is the resistivity of the material.
- L is the length of the wire.
- A is the cross-sectional area of the wire.
If the diameter of the wire is known, the cross-sectional area A can be calculated using the formula for the area of a circle:
A = π * (d/2)^2
Where d is the diameter of the wire. Once you have the cross-sectional area, you can plug it into the resistivity formula to find the resistance of the wire.