  The Helmholtz equation in one dimension, which describes the propagation of
electromagnetic waves in effectively one-dimensional systems, is equivalent to
the time-independent Schr\"odinger equation. The fact that the potential term
entering the latter is energy-dependent obstructs the application of the
results on low-energy quantum scattering in the study of the low-frequency
waves satisfying the Helmholtz equation. We use a recently developed dynamical
formulation of stationary scattering to offer a comprehensive treatment of the
low-frequency scattering of these waves for a general finite-range scatterer.
In particular, we give explicit formulas for the coefficients of the
low-frequency series expansion of the transfer matrix of the system which in
turn allow for determining the low-frequency expansions of its reflection,
transmission, and absorption coefficients. Our general results reveal a number
of interesting physical aspects of low-frequency scattering particularly in
relation to permittivity profiles having balanced gain and loss.
