A = πr2
r = d/2 = 1.628 /2 = 0.814 mm.
A 14.0 gauge copper wire of diameter 1.628 mm carries a current of 12.5 mA.
What is the potential difference across a 2.00 m length of the wire (for copper ρ = 1.72 × 10-8 Ω • m)?
What would the potential difference in part (a) be if the wire were silver instead of copper, but all else was the same (for silver ρ = 1.59 ×10-8 Ω • m)?