Electrical resistivity and conductivity conductivity in a solution. A rough summary is as follows: This table shows the resistivity (ρ), conductivity and temperature coefficient of various materials at 20 °C (68 °F, 293 K) The effective temperature coefficient varies with temperature and purity level of the material. The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at . The extremely low resistivity (high conductivity) of silver is characteristic of metals. George Gamow tidily summed up the nature of the metals' dealings with
Thermal conductivity is the electronic thermal conductivity when the electrochemical potential gradient inside the sample is zero, as a starting point. As next step the transport coefficients are written as following where formula_56 and "a" the Bohr radius. The dimensionless integrals "I" are defined as where "s"("x") is the dimensionless transport distribution function. The integrals "I" are the moments of the function where "x" is the energy of carriers. By substituting the previous formulas for the transport coefficient to the equation for "λ" we get the following equation From the previous equation we see that "λ" to be zero the bracketed term