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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.
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 thermal conductivity of a material is a measure of its ability to conduct heat.It is commonly denoted by , , or and is measured in W·m −1 ·K −1.. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity.
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 ...
The electrical resistivity, the inverse of the electrical conductivity (=), is expressed as = with for the total fluid saturated rock resistivity, and for the resistivity of the fluid itself (w meaning water or an aqueous solution containing dissolved salts with ions bearing electricity in solution).
Waterproofing, making objects or structures resist the ingress of water under specified conditions; Fluid resistance, drag in water; Lotus effect (water-resistance in plant leaves) The electrical resistivity of water (0.2 Ω·m sea water, 2 to 200 Ω·m drinking water, 180000 Ω·m deionized water at 20°C) See also: Hydrophobe; Superhydrophobe
The SI unit of absolute thermal resistance is kelvins per watt (K/W) or the equivalent degrees Celsius per watt (°C/W) – the two are the same since the intervals are equal: ΔT = 1 K = 1 °C. The thermal resistance of materials is of great interest to electronic engineers because most electrical components generate heat and need to be cooled.
Fluid conductance is a measure of how effectively fluids are transported through a medium or a region. The concept is particularly useful in cases in which the amount of fluid transported is linearly related to whatever is driving the transport.