physics, university
posted by Emma .
A 50.0g sample of a conducting material is all that is available. The
resistivity of the material is measured to be 11 x 108 ohms/m and the density is 7.86 g/cm3. The
material is to be shaped into a solid cylindrical wire that has a total resistance of 1.5 ohms.
a) What length of wire is required?
b) What must be the diameter of the wire?

m=0.05 kg, ρ =11•10⁻⁸ Ω/m
d=7860 kg/m³ R=1.5Ω
R= ρ•L/A
d=m/V=m/A•L
R/d= ρ•L²•A/A•m = ρ•L²/m.
L=sqrt{m•R/ρ•}=…
A= ρ•L/R = …
A=πD²/4
D=sqrt(4A/π)=…