2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153332Within generalized linear response theory, an expression for the dielectric function is derived which is consistent with standard approaches to the electrical dc conductivity. Explicit results are given for the first moment Born approximation. Some exact relations as well as the limiting behaviour at small values of the wave number and frequency are investigated.latex, 13 pages, 10 figures in eps formatPlasma Physicstext