Question
Which of the following is a good electrical insulator?
Answer Options
- A) Copper
- B) Glass
- C) Aluminum
- D) Mercury
Correct Answer: B
Explanation
An electrical insulator is a material that strongly resists the flow of electric current (T5A07). It does so because its electrons are tightly bound to the atoms, meaning it has very few ‘free’ electrons to carry current.
Of the choices, Glass is an excellent insulator and is often used to separate electrical potentials, such as in feed-through insulators. Copper, aluminum, and mercury are all metals and are therefore good electrical conductors.
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