🎁Question 12-Distinguish between conductors, insulators and semiconductors on the basis of conductivity and on the basis of energy bands? (Physics 2019-20 3Marks AMU +2)

 According to the energy band theory the insulators are those materials in which there is a large energy difference between valence and conduction band. The conduction band is empty, and the electrons in the valence band acquire a large amount of energy to jump in conduction band and become free. The forbidden gap is very large between valence and conduction band. That’s why the insulators did not conduct. The electric current is defined as the flow charge and there are no free electrons or holes in insulators so no current flows.

Conductors are those materials in which there is no difference of energy between valence and conduction band, or these two bands are overlapped. Electrons can easily jump from valence and conduction band. In conductors the conduction band is partially filled than those of insulators. As there are electrons is conduction band so such materials are good conductors of electricity. There is no forbidden gap between valence and conduction band in conductors.

Semiconductors are those materials in which there is a very small energy difference between valence and conduction bands and electrons and can easily jump by acquiring a small amount of energy. In semiconductors the there is a very small forbidden gap between valence and conduction bands.

Related Questions

Why is band gap important?

As the electronegativity difference Δχ increases, so does the energy difference between bonding and antibonding orbitals. The band gap is a very important property of a semiconductor because it determines its color and conductivity.

What is band model?

Band theory models the behavior of electrons in solids by postulating the existence of energy bands. It successfully uses a material's band structure to explain many physical properties of solids. Bands may also be viewed as the large-scale limit of molecular orbital theory.

Why band gap of silicon is more than germanium?

Silicon has large band gap (1.12eV) than germanium (0.7eV). So, at same temperature, the thermal pair generation in silicon is less than germanium. ... Ge has higher electron and hole mobility and because of this Ge devices can function up to a higher frequency than Si devices

🎁AMU SENIOR SECONDARY SCHOOL CERTIFICATE EXAMNINATION CLASS 12 PHYSICS 2019-20

🎁Question 1- Define Magnetic Meridian? (Physics 2019-20 1Marks AMU +2)
🎁Question 2- What is eddy current? (Physics 2019-20 1Marks AMU +2)
🎁Question 3 - An object is placed at the principal focus of a concave lens of focal length f .Where will its image be formed? (Physics 2019-20 1Marks AMU +2)
🎁Question 4-What is the phase difference In a common emitter amplifier, between the input signal voltage and output voltage ? (Physics 2019-20 1Marks AMU +2)