# Problem: In household wiring, copper wire 2.05 mm in diameter (12 gauge) is often used. Find the resistance of a 24.0 m length of this wire. Note the resistivity of copper is 1.72*10-8 Wm.

###### FREE Expert Solution

Resistance:

$\overline{){\mathbf{R}}{\mathbf{=}}\frac{\mathbf{\rho }\mathbf{L}}{\mathbf{A}}}$, where ρ is the resistivity, L is the length, and A is the cross-sectional area of the wire.

Cross sectional area:

$\overline{){\mathbf{A}}{\mathbf{=}}{\mathbf{\pi }}{{\mathbf{\left(}}\frac{\mathbf{d}}{\mathbf{2}}{\mathbf{\right)}}}^{{\mathbf{2}}}}$

###### Problem Details

In household wiring, copper wire 2.05 mm in diameter (12 gauge) is often used. Find the resistance of a 24.0 m length of this wire. Note the resistivity of copper is 1.72*10-8 Wm.