If n, e, `tau`, m, are representing electron density charge, relaxation time and mass of an electron respectively then the resistance of wire of length 1 and cross sectional area A is given by

If n, e, tau , m, are representing electron density charge, relaxation time and mass of an electron respectively then the resistance of wire of length l and cross sectional area A is given by

The resistance will be least in a wire with length, cross-section area respectively,

If the free electron density be n and relaxation time be tau , the electrical conductivity of a conductor may be expressed as

If n ,e,m and tau are free electron density in conductor , charge of electron, mass of electron and relaxation time of free electrons , then resistivity rho of the conductor can be expressed as

If n ,e,m and tau are free electron density in conductor , charge of electron, mass of electron and relaxation time of free electrons , then resistivity rho of the conductor can be expressed as