Two copper wires of length l and 2l have radii r and 2r respectively .what is the ratio of their resistivities? Share with your friends Share 7 Pratyay Ghosh answered this The resistivity of copper is constant. I guess you are asking about the resistance.R1R2=ρlAρ2lA'=ρlπr2ρ2lπ(2r)2=2 -26 View Full Answer