A research of some colloids has been carried out by means of dynamic light scattering, electrooptical and magnetooptical techniques. Intensity autocorrelation functions of scattered light have been compared to the relaxation curves of electrooptical effect for colloid particles of different shapes. The results of complex research confirm that the complicated character of light scattering by particles allows us to use the methods of birefringence and dichroism only formally when studying most colloid systems. Very thin nano-disperse structures are an exception to this rule. The investigation of polydispersity of some colloids was carried out by magnetooptical and two electrooptical techniques. Size distribution functions resulted from the different techniques agree. This justifies the suppositions about particle light scattering that are required for the use of the methods.