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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.
This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than intensive. For example, a wire's resistance is higher if it is long and thin, and lower if ...
The conductivity can in general be expressed as a tensor of the second rank (3×3 matrix). Here we restrict the discussion to isotropic, i.e. scalar conductivity. The specific resistivity is the inverse of the conductivity. Both parameters will be used in the following.
In alloys the change in electrical conductivity is usually smaller and thus thermal conductivity increases with temperature, often proportionally to temperature. Many pure metals have a peak thermal conductivity between 2 K and 10 K. On the other hand, heat conductivity in nonmetals is mainly due to lattice vibrations . Except for high-quality ...
The inverse of the resistance is known as the conductance. When we consider a metal of unit length and unit cross sectional area, the conductance is known as the conductivity, which is the inverse of resistivity. The Drude model attempts to explain the resistivity of a conductor in terms of the scattering of electrons (the carriers of ...
We have previously derived the relationship between electron mobility and current density = + = (+) Now Ohm's law can be written in the form = where is defined as the conductivity. Therefore we can write down: σ = e n μ e + e p μ h {\displaystyle \sigma =en\mu _{e}+ep\mu _{h}} which can be factorised to σ = e ( n μ e + p μ h ...
As quoted in an online version of: David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition.CRC Press. Boca Raton, Florida, 2003; Section 4, Properties of the Elements and Inorganic Compounds; Physical Properties of the Rare Earth Metals
Electrical steel is usually coated to increase electrical resistance between laminations, reducing eddy currents, to provide resistance to corrosion or rust, and to act as a lubricant during die cutting. There are various coatings, organic and inorganic, and the coating used depends on the application of the steel. [11]