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Sometime around 1913, several copper samples from 14 important refiners and wire manufacturers were analyzed by the U.S. Bureau of Standards. The average resistance of the samples was determined to be 0.15292 Ω for copper wires with a mass of 1 gram of uniform cross section and 1 meter in length at 20 °C. In the United States this is usually ...
80 K (−193 °C) 273 K (0 °C) 293 K (20 °C) 298 K (25 °C) 300 K (27 °C) 500 K (227 °C) 3 Li lithium; use 10.0 nΩm 85.3 nΩm 92.8 nΩm 94.7 nΩm 95.5 nΩm CRC (10 −8 Ωm) 1.00 8.53 9.28 9.47 9.55 LNG (10 −8 Ωm) 9.28 WEL (10 −8 Ωm) (293 K–298 K) 9.4 4 Be beryllium; use 0.75 nΩm 30.2 nΩm 35.6 nΩm 37.0 nΩm 37.6 nΩm
Ref. CRC: Values refer to 27 °C unless noted. Ref. CR2: Values refer to 300 K and a pressure of "100 kPa (1 bar)", or to the saturation vapor pressure if that is less than 100 kPa. The notation (P=0) denotes low pressure limiting values. Ref. LNG: Values refer to 300 K. Ref. WEL: Values refer to 25 °C.
Electrical conductivity is a measure of how well a material transports an electric charge.This is an essential property in electrical wiring systems. Copper has the highest electrical conductivity rating of all non-precious metals: the electrical resistivity of copper = 16.78 nΩ•m at 20 °C.
Also called chordal or DC resistance This corresponds to the usual definition of resistance; the voltage divided by the current R s t a t i c = V I. {\displaystyle R_{\mathrm {static} }={V \over I}.} It is the slope of the line (chord) from the origin through the point on the curve. Static resistance determines the power dissipation in an electrical component. Points on the current–voltage ...
Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, relative to the conductivity of pure water at 25 °C.
Kittel [8] gives some values of L ranging from L = 2.23×10 −8 V 2 K −2 for copper at 0 °C to L = 3.2×10 −8 V 2 K −2 for tungsten at 100 °C. Rosenberg [ 9 ] notes that the Wiedemann–Franz law is generally valid for high temperatures and for low (i.e., a few Kelvins) temperatures, but may not hold at intermediate temperatures.
For comparison purposes reference values are reported at an agreed temperature, usually 298 K (≈ 25 °C or 77 °F), although occasionally 20 °C (68 °F) is used. So-called "compensated" measurements are made at a convenient temperature but the value reported is a calculated value of the expected value of conductivity of the solution, as if ...