Electric light scattering measurements are reported for vapor-phase silica aggregates of different sizes, separated by centrifugation. From the correlation of electric light scattering data and time of centrifugation the fractal dimension is found to be 2.5 +/- 0.1. It is determined that the effects lie on a universal curve that reflects the scale invariance of fractal anisotropy. The investigations of silica aggregates show that the induced dipole moment rises linearly with the size of clusters, while for compact objects this dependence is power one with exponent between 2 and 3.