46. Solving a chemistry problem

185. Determine the height at which, after the establishment of diffusion-sedimentation equilibrium, the concentration of selenium hydrosol particles will decrease by half. Sol particles are spherical, particle dispersion: a) 0.2 nm^-1; b) 0.1 nm^-1; c) 0.01 nm^-1. Take the density of selenium equal to 4.81 g / cm ^ 3, the density of water is 1 g / cm ^ 3, the temperature is 298 K.