Which of the following materials is considered a good conductor?

Copper is considered a good conductor because it has a high electrical conductivity, meaning it allows electric current to flow through it with minimal resistance. This characteristic is due to its atomic structure, where one of the outer shell electrons is loosely bound and can easily move, enabling the efficient transfer of electrical energy.

Copper is widely used in electrical wiring and components because of its combination of excellent conductivity, ductility, and resistance to corrosion. Its favorable properties make it the preferred choice for various applications in the electrical and electronics industries.

The other materials listed, such as rubber, plastic, and glass, are classified as insulators. They do not allow electric current to pass through them easily, making them suitable for applications where preventing electrical flow is necessary, such as insulation for wires and safety equipment.