  We calculate the wavelength dependence of the ratio of the linear
polarization degree to extinction (polarizing efficiency)
$P(\lambda)/A(\lambda)$ from the ultraviolet to near-infrared. The prolate and
oblate particles with aspect ratios from $a/b=1.1$ up to 10 are assumed to be
rotating and partially aligned with the mechanism of paramagnetic relaxation
(Davis--Greenstein). Size/shape/orientation effects are analyzed. It is found
that the wavelength dependence of $P(\lambda)/A(\lambda)$ is mainly determined
by the particle composition and size whereas the values of
$P(\lambda)/A(\lambda)$ depend on the particle shape, degree and direction of
alignment.
