Question Detail
Question
In which of the following does the valence band overlap with the conduction band?
Correct Answer
Option A is the correct answer.
Detailed Explanation
In conductors (like metals), the valence band and conduction band overlap. This means there is no energy gap (or a very small one) that electrons need to overcome to move into the conduction band, allowing for free movement of electrons and high electrical conductivity. In semiconductors and insulators, there is an energy band gap between the valence and conduction bands.
Hint
Recall the band theory of solids. How do the energy bands differ for conductors, semiconductors, and insulators?