Which term describes a material that does not allow electrons to move freely?

Which term describes a material that does not allow electrons to move freely?

• A. Conductor
• B. Semiconductor
• C. Insulator
• D. Superconductor

Answer: (C)

Materials that don’t allow electrons to move freely have very few charge carriers and high resistance. In such insulators, electrons are tightly bound to atoms, and the energy required to reach conducting states is large, so at ordinary temperatures there’s hardly any current. That’s why insulators like rubber, glass, and wood don’t conduct electricity and are used to protect and separate electrical parts. In contrast, conductors have many free electrons that can drift when a voltage is applied; semiconductors conduct more moderately and can be controlled by temperature or doping; superconductors can carry current with zero resistance but only under special low-temperature conditions. Because of this, the term that describes a material in which electrons cannot move freely is insulator.

Materials that don’t allow electrons to move freely have very few charge carriers and high resistance. In such insulators, electrons are tightly bound to atoms, and the energy required to reach conducting states is large, so at ordinary temperatures there’s hardly any current. That’s why insulators like rubber, glass, and wood don’t conduct electricity and are used to protect and separate electrical parts. In contrast, conductors have many free electrons that can drift when a voltage is applied; semiconductors conduct more moderately and can be controlled by temperature or doping; superconductors can carry current with zero resistance but only under special low-temperature conditions. Because of this, the term that describes a material in which electrons cannot move freely is insulator.