What is the significance of Wiedemann-Franz Lorenz law?

What is the significance of Wiedemann-Franz Lorenz law?

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 expression for Wiedemann-Franz law?

It quantifies the idea that metals that are good electrical conductors are also good thermal conductors. The usual statement of the Wiedemann–Franz law is, Kσ=LT. Here K is the electrical component of the thermal conductivity, σ is the thermal conductivity, T is the absolute temperature, and L is the Lorentz number.

Which theory effectively explain electrical and thermal conductivity in metals?

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 value of Lorentz number?

The ratio of thermal to electrical conductivity, commonly known as the Lorenz number, is the same for almost all metals at a given temperature T and takes a value around 3(kB/e)2T, where kB and e are the Boltzmann constant and electronic charge, respectively.

What is electron theory of solids?

▪The electron theory of solids. aims to explain the structures and. properties of solids through their. electronic structure. ▪The electron theory of solids has.

Are Diamonds heat resistant?

Most diamonds are extremely efficient thermal conductors, but electrical insulators. Diamond conducts heat well as a result of the strong covalent bonds between carbon atoms in a diamond crystal.

Is Diamond thermal conductivity?

Diamond is the most highly prized of gemstones. Along with its carbon cousins graphite and graphene, diamond is the best thermal conductor around room temperature, having thermal conductivity of more than 2,000 watts per meter per Kelvin, which is five times higher than the best metals such as copper.

Do metals expand when heated?

Metal expands when heated. Length, surface area and volume will increase with temperature. The degree of thermal expansion varies with different types of metal. Thermal expansion occurs because heat increases the vibrations of the atoms in the metal.

What is the difference between electrical conductivity and thermal 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 classical free electron theory?

A classical free electron theory is a macroscopic theory proposed by Paul Drude in 1900. After the discovery of electron by JJ Thomson, this theory was elaborated by Lorentz in 1909. According to this theory, the free electrons move with a constant potential obeys quantum laws (Fermi-Dirac statistics).

Do solids have free moving electrons?

In a conductor the electrons in the conduction band are shared by all the atoms of the solid, from the time of construction of the solid. They do not go from the valence band to the conduction after the lattice is formed. That is why the electrons are sometimes thought as “free”.