1. The problem statement, all variables and given/known data A 10-g piece of copper is to be formed into a wire of radius 1.0 mm at a temperature of 50° C. What is the resistance of this wire? (Hint: you will need to look up the density of copper.) If a potential of 12 V is put across this wire, what is the drift velocity? 2. Relevant equations J=I/A=nqvd R=ρ(L/A) ρ=ρ0(1+[itex]\alpha[/itex](T-T0) ρ0=1.7*10^-8 at 20°C 3. The attempt at a solution The resistivity of copper at 50°C is: ρ=ρ0(1+[itex]\alpha[/itex](T-20) where [itex]\alpha[/itex]=3.9*10^-3 1/°C Substituting values, ρ=1.899*10^-8 Ωm I hit a brick wall here, though. I don't know how to get from density of copper to length of the wire for R=ρ(L/A) Any advice?