#### Answer

σ = 6.67 x $10^{6}$ $(Ω-m)^{-1}$ (Answers may slightly vary.)

#### Work Step by Step

Given:
Tensile strength of Cu-Ni = 275 MPa (40,000psi)
Required:
Electrical conductivity of Cu-Ni
Solution:
From Figure 7.16a, the composition of an alloy having 275 MPa is about 10 wt% Ni.
From Figure 18.9, the resistivity of this composition is about 15 x $10^{-8}$ Ω-m
As conductivity is the reciprocal of resistivity (Equation 18.4),
σ = $\frac{1}{p}$ = $\frac{1}{15 \times10^{-8} Ω-m}$
σ = 6.67 x $10^{6}$ $(Ω-m)^{-1}$