Where K and σ are thermal and electrical conductivities in a solid, according to Wiedemann-Franz law

CONCEPT:Wiedemann-Franz law states that the ratio between the electronic contribution of the thermal conductivity (k) and electrical conductivity (σ) of metal is proportional to the temperature (T).MATHEMATICALLY it is written as\(\Rightarrow \frac{{\bf{k}}}{{\bf{\sigma }}} = {\bf{LT}}\)Or, \(\frac{{\bf{k}}}{{{\bf{\sigma T}}}} = {\bf{L}}\)Where L = Lorenz number (proportionality constant) and is EQUAL to 2.44 × 10-8 W Ω K-2.EXPLANATION:From the above, it is clear that the Wiedemann-Franz law connects the thermal conductivity and electrical conductivity of a material. Therefore option 1 is correct.Wiedemann-Franz law QUANTIFIES the IDEA that the metals which are the best electrical CONDUCTORS are also the best thermal conductors.