How does temperature generally affect resistance in most metal conductors?

How does temperature generally affect resistance in most metal conductors?

• A. Resistance increases with temperature
• B. Resistance decreases with temperature
• C. No effect
• D. Depends on metal

Answer: (A)

As temperature rises, resistance in most metal conductors goes up. That happens because hotter temperatures make the atoms in the metal vibrate more, which increases collisions (scattering) of moving electrons with those vibrating atoms. More scattering slows the electrons and raises resistivity. This relationship is often written as R ≈ R0[1 + α(T − T0)], where α is the positive temperature coefficient of resistivity for metals. For example, copper has α about 0.0039 per degree Celsius, so a 50°C increase would raise resistance by roughly 19%. This trend is typical for metals; other materials, like many semiconductors, can behave differently, with resistance decreasing as temperature rises.

As temperature rises, resistance in most metal conductors goes up. That happens because hotter temperatures make the atoms in the metal vibrate more, which increases collisions (scattering) of moving electrons with those vibrating atoms. More scattering slows the electrons and raises resistivity.

This relationship is often written as R ≈ R0[1 + α(T − T0)], where α is the positive temperature coefficient of resistivity for metals. For example, copper has α about 0.0039 per degree Celsius, so a 50°C increase would raise resistance by roughly 19%. This trend is typical for metals; other materials, like many semiconductors, can behave differently, with resistance decreasing as temperature rises.