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?
ρ0=1.7*10^-8 at 20°C
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)