As temperature increases, what happens to the resistivity of metals?

• A. It decreases
• B. It remains constant
• C. It becomes zero
• D. It increases

Answer: (D)

In metals, resistivity increases with temperature because lattice vibrations (phonons) become more pronounced as temperature rises. Those vibrations scatter conduction electrons more frequently, hindering their flow and raising the resistive opposition. This creates a positive temperature coefficient of resistivity, often approximated by ρ ≈ ρ0(1 + αT) with α > 0 over a broad range. The other options imagine zero resistance or no change, which would not describe ordinary metallic behavior. Thus the resistivity increases with temperature.