Question

Which relation expresses the macroscopic form of Ohm’s law used to identify conductivity?

Options

• \[I=neAv_d\]

• \[a=-\frac{eE}{m}\]

• \[j=\sigma E\]

• \[j=\frac{I}{A}\]

Answer 1

The relation \[j=\sigma E\] connects current density with electric field through conductivity. Comparing it with the microscopic expression yields the formula for \[\sigma\].