Additional 2 Marks Question & Answers

ADDITIONAL '2' Marks - Q&A

1. What is electron theory of solids?

The electrons in the outermost orbit of the atoms which constitute the solids determine its electrical properties. The electron theory of solids explains the structure and properties of solids through their electronic structure.

2. What are special features of classical free electron theory of solids?

In a metal, the free electrons of an atom are free to move about the entire volume of the metal like the molecules of a perfect gas in a container. These free electrons in the metal are responsible for electrical conduction.

3. What is a periodic potential.

When an electron moves through a solid, its potential energy varies periodically with the periodicity equal to period of space lattice 'a' (interatomic distance). This is called periodic potential.

4. What is an energy band?

A set of closely spaced energy levels is called an energy band.

5. What is an effective mass of electron?

The mass acquired by an electron when it is accelerated in a periodic potential is called effective mass of an electron. It is denoted by m.