A copper-silver bimetallic wire, 1 cm in diameter, is prepared by co-extrusion with copper as the core and silver as the outer layer. The desired properties along the axis parallel to the length of the bimetallic wire are as follows:

            a. thermal conductivity > 410 W/(m-K)

            b. electrical conductivity > 60 x 10^6 Ω-1 m -1

            c. weight< 750 g/m

Determine the allowed range of the diameter of the copper core.

(Copper: density = 8.96 g/cm^3, electrical conductivity = 59 x 10^6, thermal conductivity =401; Silver: density = 10.49, electrical conductivity = 63 x 10 ^6, thermal conductivity = 429)