Band Theory of Solids
Physics ⇒ Modern Physics
Band Theory of Solids starts at 11 and continues till grade 12.
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See sample questions for grade 11
A material has a band gap of 2.5 eV. Is it more likely to be a semiconductor or an insulator?
Describe how the band theory accounts for the difference in electrical conductivity between copper and diamond.
Describe the effect of light on the conductivity of a semiconductor.
Describe what happens to the band gap of a semiconductor when it is heavily doped.
Describe what happens to the band structure of a solid as the number of atoms in the crystal increases.
Explain the difference between a valence band and a conduction band.
Explain why insulators do not conduct electricity under normal conditions.
Explain why the band gap is important in determining the electrical properties of a material.
Which of the following best describes a conductor according to band theory?
(1) The valence band is completely filled and the conduction band is empty.
(2) The valence band and conduction band overlap.
(3) There is a large energy gap between the valence and conduction bands.
(4) The valence band is partially filled.
Which of the following best describes the band structure of a semiconductor at absolute zero?
(1) The conduction band is partially filled.
(2) The valence band is completely filled and the conduction band is empty.
(3) Both bands are partially filled.
(4) The valence band is empty.
Which of the following best explains why metals are good conductors?
(1) They have a large band gap.
(2) Their conduction band is partially filled or overlaps with the valence band.
(3) Their valence band is completely filled.
(4) They have no electrons in the conduction band.
Which of the following is a typical band gap value for silicon?
(1) 0.1 eV
(2) 1.1 eV
(3) 3.5 eV
(4) 5.0 eV
Fill in the blank: In a semiconductor, the energy gap is ______ than that in an insulator.
Fill in the blank: In metals, the Fermi level lies ______ the conduction band.
Fill in the blank: The band theory of solids is based on the concept of ______ overlap in a crystal lattice.
Fill in the blank: The electrical conductivity of an insulator is ______ compared to that of a conductor.
True or False: At absolute zero, all electrons in a semiconductor occupy the conduction band.
True or False: Doping a semiconductor can change its electrical conductivity.
True or False: In an insulator, the energy gap between the valence band and conduction band is very small.
True or False: The band gap of a material can be measured using optical absorption experiments.
