What is true about materials that are good electrical conductors?

Materials that are good electrical conductors, such as copper and aluminum, typically also possess good thermal conductivity. This correlation arises because the properties that allow electrons to move easily through a conductor and carry electrical current are often similar to those that allow heat to transfer efficiently. In many metals, the free electrons that facilitate electrical conduction also play a significant role in the conduction of heat. This dual capability is essential in practical applications, where materials like copper are frequently used not only in wiring but also in components that require effective heat dissipation, such as heat exchangers and radiators in HVAC systems.

The other options do not accurately represent the characteristics of electrical conductors. Good insulators are the opposite of conductors and would not share conductive properties. While some conductive materials can be heavy, there are numerous lightweight materials that are also excellent conductors, so weight is not a defining characteristic. Lastly, the assertion that conductive materials can only be used for electricity is misleading, as they are widely utilized in applications involving thermal management, showcasing their versatile roles in both electrical and thermal contexts.