How does resistance change with temperature for most conductors?

How does resistance change with temperature for most conductors?

• A. It decreases with temperature
• B. It stays the same with temperature
• C. It increases with temperature
• D. It fluctuates with temperature

Answer: (C)

The main idea is that most metal conductors have a positive temperature coefficient of resistance: their resistance increases as temperature rises. As temperature goes up, the atoms in the metal lattice vibrate more vigorously. These vibrations create more obstacles for the free electrons moving through the metal, causing more collisions and scattering. That extra scattering slows the electrons and raises resistivity, so the overall resistance goes up with temperature. A handy way to remember this is that metals typically follow R ≈ R0[1 + α(T − T0)] with a positive α. There are exceptions, like semiconductors, where resistance can decrease with increasing temperature, but for typical metal conductors, resistance increases with temperature.

The main idea is that most metal conductors have a positive temperature coefficient of resistance: their resistance increases as temperature rises. As temperature goes up, the atoms in the metal lattice vibrate more vigorously. These vibrations create more obstacles for the free electrons moving through the metal, causing more collisions and scattering. That extra scattering slows the electrons and raises resistivity, so the overall resistance goes up with temperature. A handy way to remember this is that metals typically follow R ≈ R0[1 + α(T − T0)] with a positive α.

There are exceptions, like semiconductors, where resistance can decrease with increasing temperature, but for typical metal conductors, resistance increases with temperature.