Britannica Sources used in this answer

How can the resistance of a copper wire be calculated at room temperature?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

density current: descent to the ocean floor — density current Diagram showing the behaviour of a density current as it descends to the seafloor.

To calculate the resistance ( $R$ ) of a copper wire at room temperature, you use the following formula:

$R = ρ \frac{l}{A}$

In this equation:
* $ρ$ (rho) is the resistivity of the material. For copper at room temperature, this value is approximately $1.7 \times 10^{- 8}$ ohm-metres.1
* $l$ is the length of the wire in metres.1
* $A$ is the cross-sectional area of the wire in square metres.1

The resistance is directly proportional to the length of the wire and inversely proportional to its cross-sectional area. By substituting the specific resistivity of copper and the physical dimensions of your wire into this formula, you can determine its total resistance in ohms.12