# Stokes-Einstein equation

## Description

According to Stokes’ law, a perfect sphere traveling through a viscous liquid feels a drag force proportional to the frictional coefficient. The diffusion coefficient D of a sherical particle istproportional to its mobility: Substituting the frictional coefficient of a perfect sphere from Stokes’ law by liquid’s viscosity and sphere’s radius we have Stokes-Einstein equation.

Related formulas## Variables

D | Diffusion coefficient (m^{2}/s) |

k_{B} | Boltzmann constant |

T | The temperature (K) |

π | pi |

n | The dynamic viscosity (Pa*s) |

r | The radius of the spherical practicle (m) |