What is the difference between a conductor and an insulator?

• A. Conductors allow current; insulators resist current.
• B. Insulators allow current; conductors resist current.
• C. Conductors store electrical energy.
• D. Insulators have very low resistance.

Answer: (A)

Electric flow depends on how easily a material lets charges move. A conductor has many free electrons that can drift when a voltage is applied, so current passes through it with only a small resistance. An insulator, on the other hand, holds its electrons tightly and resists their movement, so it blocks or greatly slows current and has high resistance. That’s why wires are made of conductors like copper but coated with insulating material like plastic to keep the current where it should go and protect you. The idea that conductors store electrical energy isn’t the defining feature, and insulators having very low resistance is incorrect because they resist current.