Which statement best defines an insulator?

• A. Materials that offer high resistance to electron movement.
• B. Materials that conduct electricity easily.
• C. Materials that store charge.
• D. Materials that generate current.

Answer: (A)

An insulator is defined by its high resistance to the movement of electric charges. In insulators, electrons are tightly bound to atoms, so they don’t flow easily and only a very small current passes through at normal voltages. This is why materials like rubber, glass, and plastic are used to coat or separate conductors—to keep current from leaking where it shouldn’t go. If you push voltage high enough, some insulators can break down and conduct, but under everyday conditions they block current. The idea that stores charge or generates current isn’t what defines an insulator—the key property is resisting electron movement.