Question

Energy band gap between valence band and conduction band for insulator is:

• A. Zero
• B. greater than $9eV$
• C. less than conductors
• D. approximately $1eV$

Answer 1

Answer: (B)

greater than $9eV$

An insulator does not have any electrons in its conduction band at room temperature. This implies that the energy of the electrons at room temperature is insufficient to jump from the valence band to the conduction band. Therefore, an insulator has significant band gap. The gap must be greater than 9eV.