The Wiedemann-Franz law describes the relationship between the electrical conductivity, temperature, and carrier concentration in a metal. It states that: σ =...
The Wiedemann-Franz law describes the relationship between the electrical conductivity, temperature, and carrier concentration in a metal. It states that:
σ = α * e^(-E_c/kT)
where:
σ is the electrical conductivity
α is a dimensionless constant that depends on the material and temperature
e is the base of the natural logarithm
E_c is the minimum conduction energy, which is the amount of energy required to remove an electron from the metal
k is Boltzmann's constant
T is the temperature
The key points of the Wiedemann-Franz law are:
It is a quantitative relationship between the three variables
It applies to all metals, regardless of their chemical composition
It is valid at low temperatures
It becomes less accurate at high temperatures
Examples:
For example, the Wiedemann-Franz law predicts that the conductivity of metals increases with increasing temperature.
In contrast, the conductivity of insulators decreases with increasing temperature.
The Wiedemann-Franz law is used in various applications, such as the design of electrical conductors and thermal batteries