Question
Which of the following are correct for insulators?

Answer

  1. The conduction band is empty and the valence band is filled with electrons.
Explanation:
In insulators, the electrons are very tightly bound to the nucleus. At a room temperature, thermal energy is not enough to push electrons into conduction band. The energy band gap is very high. Thus the conduction band is empty and the valence band is filled with electrons.

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