Question

Draw and explain temperature dependence of relation of thermal and electrical conductivity for real metals

Answer 1

In metals when temperature increases it leads to the increase in the vibration of the electrons in the lattice. It causes restriction to the motion of electrons as the number of collision increases ie drift velocity decreases. resistance is inversely proportional to drift velocity so decrease in drift velocity leads to increase in resistance (in fact resistivity because there is no change in dimension of the sample ie length and cross section)  so it becomes difficult for the current to pass through it.

So increase in temperature results in decrease in electrical conductivity.

Electrical conductivity vs temperature graph is given below.

Thermal conductivity is a constant for a material. It is different for different material.