Which of the following materials is the best electrical conductor?
A. Aluminum resistivity= 4.6E-8
B. Brass resistivity=7.0E-8
C. Copper resistivity=1.8E-8
D. Nichrome resistivity=105E-8
Answer: C.
Resistance = ρL/A, where ρ is the resisitivity, L the length, and A the area of cross section of the conductior.
So, if we consider L/A to be the same for all conductors,
the conductor with lower ρ will have a lower resistance, and hence will be the better conductor.
So, Copper with the lowest resistivity is the best conductor.