Define the term resistivity and write its S.I. unit. Derive the expression for the resistivity in terms of number density of free electrons and relaxation time.

What is meant by resistivity ? Write its S.I. unit.

Explain how does resistivity of a conductor depend upon number density n of free electron relaxation time tau ?

Express electrical conductivity in terms of charge, mass, number density and relaxation time.

Explain how the resistivity of a conductor depends upon number density 'n' of free electrons?

Using the concept of free electrons in a conductor, derive the expression for the conductivity of a wire in terms of number density and relaxation time. Hence obtain the relation between current density and the applied electric field E.

Derive an expression for drift velocity of free electrons in a conductor in terms of relaxation time.

Define resistance and give its units?

Define the term bond enthlphy. Give its unit.