Increasing temperature increases the resistance due to increase in movement of electrons right? In a conductor through which current flows.

Answer 1

Hello,

In a simplified picture, we can think of electrical conduction as electrons moving through a lattice, which is an arrangement of particles that make up the conducting material's structure. Although this lattice is usually thought of as "stationary" relative to the moving electrons, it still has vibrational energy (what is referred to as "phonons" -- not to be confused with photons!).

The vibration of this lattice is dependent on the temperature of the material, with higher temperatures corresponding to a greater number of phonons (vibrations). If there is an increased number of lattice vibrations due to increasing temperature, then the moving electrons are more likely to "bump" into the lattice and thus have their movement hindered. The result is what we observe as an increase in resistance (or equivalently, a decrease in conductivity). An analogy: it is harder for you (the electron) to make your way through a dense crowd of people (the lattice) if those people are each individually moving rapidly within the crowd. The higher the temperature (the crowd's "excitement") the slower your movement through that crowd will be.

In summary: higher temperatures lead to increase in lattice vibrations, which makes it more difficult for the electrons to flow through this lattice. A reduction of electron flow means we have increased resistance.