Question

Explain electrical properties of solid on the basis of band theory.​

Answer 1

Answer:

Depending upon the electrical conductivities the solids are classified in given three types:-

Conductors:-

The solids which have the conductivity in range 104 to 107 ohm-1 are called the conductors metals are called the best conductors of electricity.

Insulators:-

The solids which have extremely low conductivities ranging between 10-20 to 10-10 ohm are called insulators.

Example: Plastics, Wood, Rubber etc.

Semiconductors:-

The solids which have conductivity in between those of conductors and insulators are called the semiconductors.

Example: Silicon, Germanium etc

Answer 2

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On the basis of band theory the solid can be conductors, insulator or semiconductor.

• Conductors conduct electricity electrics through the movement of electrons (metals) or ions (electrolytes).

• The atomic orbitals of metals form molecular orbitals that is so close in energy which is form bonds.

• In semiconductor, the gap is small. For example, silicon and germanium. Their conductivity which can be increased by adding impurity which can be electron rich or electron deficient.

• When increase in conductivity is due to the electron - rich impurity, that type of conductivity is called n-type semiconductor.

• When the increase in conductivity is due to electron-deficient impurity, it is called p-type semiconductors.