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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.
Sheet resistance is a special case of resistivity for a uniform sheet thickness. Commonly, resistivity (also known as bulk resistivity, specific electrical resistivity, or volume resistivity) is in units of Ω·m, which is more completely stated in units of Ω·m 2 /m (Ω·area/length). When divided by the sheet thickness (m), the units are Ω ...
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
In this case, the carrier density (in this context, also called the free electron density) can be estimated by: [5] n = N A Z ρ m m a {\displaystyle n={\frac {N_{\text{A}}Z\rho _{m}}{m_{a}}}} Where N A {\displaystyle N_{\text{A}}} is the Avogadro constant , Z is the number of valence electrons , ρ m {\displaystyle \rho _{m}} is the density of ...
In this case the conductivity of purified water often is 10 to 20 times higher. A discussion can be found below. Typical drinking water is in the range of 200–800 μS/cm, while sea water is about 50 mS/cm [3] (or 0.05 S/cm). Conductivity is traditionally determined by connecting the electrolyte in a Wheatstone bridge.
The van der Pauw Method is a technique commonly used to measure the resistivity and the Hall coefficient of a sample. Its strength lies in its ability to accurately measure the properties of a sample of any arbitrary shape, as long as the sample is approximately two-dimensional (i.e. it is much thinner than it is wide), solid (no holes), and the electrodes are placed on its perimeter.
The resistivity of different materials varies by an enormous amount: For example, the conductivity of teflon is about 10 30 times lower than the conductivity of copper. Loosely speaking, this is because metals have large numbers of "delocalized" electrons that are not stuck in any one place, so they are free to move across large distances.
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 ...