Why do metals often make good conductors of electric charge $q$?

• A. Because metals have tightly bound electrons that do not move.
• B. Because metals have a high resistance $R$ to the flow of electric charge $q$.
• C. Because metals are always magnetic.
• D. Because metals have free electrons $e$ that can move easily throughout the material.

Answer: (D)

Verified step by step guidance

1. Understand that electrical conductivity depends on the availability of charge carriers that can move freely within a material.
2. Recall that in metals, some electrons are not tightly bound to individual atoms but are free to move throughout the metal lattice; these are called free or conduction electrons.
3. Recognize that these free electrons can respond to an electric field by drifting through the metal, allowing electric charge to flow easily.
4. Contrast this with materials where electrons are tightly bound and cannot move freely, resulting in poor conductivity.
5. Conclude that metals make good conductors because their structure provides a 'sea' of free electrons that facilitate the flow of electric charge.