Similarly, one can derive an equivalent formula for identical charged particles of charge q in a uniform electric field of magnitude E, where mg is replaced with the electrostatic force qE. Equating these two expressions yields the Einstein relation for the diffusivity, independent of mg or qE or other such forces:
One can derive an equivalent formula for identical charged particles of charge q in a uniform electric field of magnitude E, where mg is replaced with the electrostatic force qE.  This yields the Einstein relation for diffusivity, which is independent of mg or qE or other such forces.