What effect does heating a conductor usually have on its resistance?

Heating a conductor typically leads to an increase in its resistance due to the increased thermal motion of the atoms within the material. As temperature rises, the atoms vibrate more vigorously, which in turn causes greater collisions between the free electrons (carriers of electricity) and these vibrating atoms. This heightened interaction impedes the flow of electrons, thereby increasing resistance.

In metallic conductors, which are most commonly used in electrical applications, this phenomenon is quite evident. The relationship between temperature and resistance is defined by the temperature coefficient of resistance for the material, which indicates how much the resistance will change with temperature. Common conductors like copper and aluminum show a significant increase in resistance with an increase in temperature, making this effect crucial for electrical circuit design and performance.

In special circumstances, such as with superconductors, resistance can drop to zero below a critical temperature, but for conventional conductors, the overall trend remains that resistance increases with temperature. Understanding this behavior is vital for ensuring that electrical systems operate efficiently and safely under varying conditions.