The Wiedemann-Franz law states that the ratio of thermal conductivity to the electrical conductivity of a metal is proportional to its temperature. The law can be explained by the fact that free electrons in the metal are involved in the mechanisms in both heat and electrical transport.
What is the ratio of the thermal conductivity to electrical conductivity equal to?
In physics, the Wiedemann–Franz law states that the ratio of the electronic contribution of the thermal conductivity (κ) to the electrical conductivity (σ) of a metal is proportional to the temperature (T).
What is the ratio of thermal conductivity to electrical conductivity Mcq?
Is thermal conductivity same as electrical conductivity?
By definition, electrical conductivity is a measure of how well electrical current (charge in motion) can pass through a material under the influence of an applied voltage/electric field. Thermal conductivity measures how well heat (thermal energy in motion) can pass through a material under a temperature differential.
What is relationship between electrical conductivity and temperature?
The conductivity invariably increases with increasing temperature, opposite to metals but similar to graphite. It is affected by the nature of the ions, and by viscosity of the water. In low ionic concentrations (very pure water), the ionization of the water furnishes an appreciable part of the conducting ions.
What is Wiedemann-Franz Lorenz law?
The Wiedemann–Franz Law (1853) states that the ratio of the electronic contribution of the thermal conductivity κ to the electrical conductivity σ of a metal is proportional to the temperature T based on a semi-classical treatment of the electron gas [11, 24].
How is Lorentz number calculated?
Because the charge carriers (electrons in n-type or holes in p-type semiconductors) transport both heat and charge, κE is commonly estimated using the measured σ using the Wiedemann-Franz law: κE = LσT, where L is the Lorenz number.