Question

A hundred particles of equal size and density are released simultaneously and allowed to settle in still air for 5 min. Because of Brownian motion along the vertical axis, some particles will progress farther than others. If the particles are 0.6-?m spheres of standard density, what are the mean and standard deviation of their displacements from origin after 5 min?

[Answer 4.1 mm, 0.17 mm]

Answer 1