If 46 m of nichrome wire is to have a resistance of 12.0 Ω at 20°C, what diameter wire should be used? in mm
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 Nichrome 150e-8 Ω-m 12 = (150e-8 Ω-m)(46m)/(πr?) solve for r, which would be the radius of the wire in meters. change to mm, and multiply by 2 to get diameter. .
