AIIMS 2019 Physics Conductivity and Resistivity MCQ Question

When temperature increases, the random motion of electrons and vibrations of ions intensifies, leading to more frequent collisions between electrons and ions. This results in a decrease in the average time between successive collisions (τ), which in turn increases the conductivity (σ) of the material, as conductivity is inversely related to resistivity (ρ). Consequently, resistivity increases (option B) and conductivity decreases (option C) are incorrect, as higher temperatures typically enhance electron mobility, thereby increasing conductivity. Option D is also incorrect since resistivity is expected to rise with temperature in conductive materials.