valence band is empty and conduction band is filled with electrons.
conduction band is empty and valence band is completely filled with electrons.
valence band is partially filled.
conduction band is partially filled with electrons.
Solution
Insulators are the materials which do not conduct electricity. All the electrons are filled in valance band whereas the conduction band is empty. Moreover, the enerw band gap in insulators is very large, thus electrons cannot jump from valence band to conduction band.
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