Temperature Dependence of Resistivity: The resistivity of a material is often temperature dependent, meaning that it can change with changes in temperature. The temperature dependence of resistivity is influenced by various factors, including the structure of the material, the presence of impurities, and the type of material (conductor, semiconductor, or insulator).

For most conductors (e.g. metals), resistivity generally increases with temperature. This is because an increase in temperature can cause an increase in thermal energy, which can cause the electrons to collide more frequently with each other and with the lattice structure of the material. These collisions can scatter the electrons, reducing their mobility and increasing the resistivity of the material.

For some semiconductors, such as silicon and germanium, resistivity decreases with temperature. This is because an increase in temperature can increase the concentration of free electrons and holes (positive charges), making it easier for electrical current to flow through the material.

Temperature Dependence of Resistivity

The resistivity’s of metallic conductors within a limited range of temperature are given by the following equation:

ρ_T= ρ₀ [1 + a(T–T₀)]

Here,

ρ_T = resistivity at a temperature T

ρ₀ = resistivity at a reference temperature T₀

a = temperature coefficient of resistivity; the dimension of a is (Temperature)^-1

According to the above equation, a graph of ρ_T plotted against T would be a straight line i.e., the resistivity of a metallic conductor increases with increasing temperature.

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By Team Learning Mantras