Solid-state physics: Why are metals good conductors of electricity? Select the primary microscopic reason for high electrical conductivity in metals at ordinary temperatures. Choose the correct option.
IIT JEE
Physics
Difficulty: Easy
Choose an option
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ABecause their atoms are very light
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BDue to the presence of many free (delocalized) electrons in a conduction band
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CBecause metals have high specific heat
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DBecause metals strongly attract electrons and hold them tightly
Answer
Correct Answer: Due to the presence of many free (delocalized) electrons in a conduction band
Explanation
ConceptIn metals, valence and conduction bands overlap or the conduction band is partially filled. Electrons are delocalized ('free'), allowing drift under an electric field ⇒ high conductivity.
ContrastInsulators have large band gaps; semiconductors have fewer carriers at room temperature unless doped.
Final AnswerDue to the presence of many free (delocalized) electrons in a conduction band