  We compare two different models of transport of light in a disordered system
with a spherical Gaussian distribution of scatterers. A coupled dipole model,
keeping into account all interference effects, is compared to an incoherent
model, using a random walk of particles. Besides the well known coherent
backscattering effect and a well pronounced forward lobe, the incoherent model
reproduces extremely well all scattering features. In an experiment with cold
atoms, we use the momentum recoil imparted on the center of mass of the sample
as a partial probe of the light scattering properties. We find that the force
acting on the center of mass of the atoms is not well suited to exhibit the
coherence effects in light propagation under multiple scattering conditions.
