Question

what are the main drawbacks in quantom free electron theory

Answer 1

1. Classical theory states that all free electrons absorb the supplied energy. But quantum theory states that only a few electron absorb the supplied energy.

2. The electrical conductivity of semiconductor and insulator cannot be explained by this theory.

3. The concept of photo - electric effect, Compton effect and black body radiation cannot be explained on the basis of this theory because these phenomenon are based on quantum theory.

4. The susceptibilities of a paramagnetic material is inversely proportional to the temperature. But, experimental result shows that para-magnetism of a metal is independent of temperature. Moreover, the ferro-magnetism cannot be explained by this theory.