A polystyrene sphere of radius is dispersed in water at

PHYSICS · Multi-part · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Soft condensed matter · Soft condensed matter

Soft Matter at the Thermal Scale, Ch Brownian particles, sedimentation and the hard-sphere fluid

Problem

A polystyrene sphere of radius a=250 nma = 250\,\mathrm{nm} is dispersed in water at 298 K298\,\mathrm{K}, with solvent viscosity η=0.89 mPa s\eta = 0.89\,\mathrm{mPa\,s} and kBT=4.11×10−21 Jk_BT = 4.11\times10^{-21}\,\mathrm{J}. ((a)) Find the free-particle diffusion coefficient D0D_0. ((b)) Find the Brownian time τB=a2/D0\tau_{\rm B} = a^2/D_0.

Browse the problem library