  The theory of first order density-driven phase transitions with frustration
due to the long range Coulomb (LRC) interaction develop on paper I of this
series is applied to the following physical systems: i) the low density
electron gas ii) electronic phase separation in the low density three
dimensional $t-J$ model iii) in the manganites near the charge ordered phase.
We work in the approximation that the density within each phase is uniform and
we assume that the system separates in spherical drops of one phase hosted by
the other phase with the distance between drops and the drop radius much larger
than the interparticle distance. For i) we study a well known apparent
instability related to a negative compressibility at low densities. We show
that this does not lead to macroscopic drop formation as one could expect
naively and the system is stable from this point of view. For ii) we find that
the LRC interaction significantly modifies the phase diagram favoring uniform
phases and mixed states of antiferromagnetic (AF) regions surrounded by
metallic regions over AF regions surrounded by empty space. For iii) we show
that the dependence of local densities of the phases on the overall density
found in paper I gives a non-monotonous behavior of the Curie temperature on
doping in agreement with experiments.
