what is the resistance of a copper bus bar 10 meters long and .3 x .3 cm in cross section?
Resistance of a wire in Ω R ρL/A ρ is resistivity of the material in Ω-m L is length in meters A is cross-sectional area in m? A πr?, r is radius of wire in m resistivity Cu 17.2e-9 Ω-m Assuming you mean the bar has a square cross-section. A 0.3? 0.09 cm? 9e-6 m? R (10)(17.2e-9) / (9e-6) 0.0191 ohms
