The resistivity of copper as a function of temperature is given approximately by ? = ?₀[1 + a(T - T₀)], where ?₀ is Table 24.1?s entry for 20?C, T0 = 20?C, and a = 4.3x10^-3 ?C^-1 . Find the temperature at which copper?s resistivity is twice its room temperature value.

Transcribed Image Text:

Table 24.1 Resistivities Material Resistivity (2-m) Metallic conductors (20°C) Aluminum 2.65 x 108 Сорper 1.68 x 108 Gold 2.24 x 108 Iron 9.71 x108 Mercury 9.84 x 10-7 1.59 x 108 Silver Ionic solutions (in water, 18°C) 1-molar CuSO, 3.9x 104 1-molar HCI 1.7×102 1-molar NaCI 1.4x 104 H20 2.6x 105 Blood, human 0.70 Seawater (typical) 0.22 Semiconductors Germanium 0.5 Silicon 3x 10 Insulators Ceramics 101-1014 Glass 1010-1014 Polystyrene 1015–107 Rubber 103-1016 Wood (dry) 10-1014