1.0 cm³ of copper is drawn out into the form of a long wire of cross-sectional area 4.0 × 10⁻⁷ m².

Calculate its resistance. (Use the resistivity value for copper from Table 10.2.)

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Material Resistivity / m silver 1.60 x 10-8 copper 1.69 x 10-8 nichrome(a) 1.30 x 10-8 aluminium 3.21 x 10-8 lead 20.8 x 10-8 manganin(b) 44.0 x 10-8 eureka(c) 49.0 x 10-8 mercury 69.0 x 10-8 graphite 800 x 10-8 germanium 0.65 silicon 2.3 x 103 Pyrex glass 1012 PTFE(d) 1013-1016 quartz 5 x 1016 (a) Nichrome - an alloy of nickel, copper and aluminium used in electric heaters because it does not oxidise at 1000 °C. (b) Manganin - an alloy of 84% copper, 12% manganese and 4% nickel. (c) Eureka (constantan) - an alloy of 60% copper and 40% nickel. (d) PTFE - Poly(tetrafluoroethene) or Teflon.