UNIT I FREE ELECTRON THEORY, CFET, QFET, EF, DOS

In solids, _________in outer most orbits of atoms determine its electrical properties

• protons

• neutron

• electrons

• positron

Free electron theory has been developed in ----------- main stages

• 1

• 2

• 3

• 5

This theory was developed by Drude & Lorentz in 1900

• Classical free electron theory

• Quantum free electron theory

• Zone theory

• Bloch theory

Sommerfield developed the quantum free electron theory in

• 1956

• 1900

• 1927

• 1928

According to this theory, free electrons move in a periodic potential provided by the lattice

• Classical free electron theory

• Quantum free electron theory

• free electron theory

• zone theory

In CFET, free electrons move in

• unidirection

• bidirection

• random direction

• one path

There is no loss of energy and resultant velocity is zero, this indicates ______ of free electrons

• inelastic collision

• elastic collision

• Direct compact

• Oblique impact

When an electric field is applied to the metal, the free electrons move in (a)   direction

Pick out the odd one.

• fails to explain the specific heat capacity of metals

• explains new phenomena like photoelectric effect, Compton effect, black – body radiation

• Susceptibility has greater theoretical value than the experimental value

• fails to explain superconducting properties of metals

In QFET, Energy levels are

• discrete

• continuous

• discontinuous

• has increasing value