Which of the following is a conductor?

• A. A conductor
• B. An insulator
• C. A semiconductor
• D. A dielectric

Answer: (A)

A material that conducts electricity allows charges to move easily because it has many free charge carriers. In conductors, these charge carriers, often electrons, are delocalized and can respond quickly to an applied voltage, producing a current with relatively low resistance. The option that describes a conductor matches this property exactly, which is why it’s the best choice.

In contrast, an insulator resists current because its electrons are tightly bound and don’t move easily; a dielectric is a type of insulator used to store electric charge in devices like capacitors; a semiconductor has conductivity that is between a conductor and an insulator and depends on factors such as temperature and impurities.