# Definition of Stokes' law in English:

## Stokes' law

### proper noun

Physics
• 1A law stating that in fluorescence the wavelength of the emitted radiation is longer than that of the radiation causing it. This is not true in all cases.

• ‘From Stokes' law, this works out to a thrust of ~ 0.5 pN.’
• ‘He applied it to explain Stokes' law, ionisation of gas by ultraviolet light and the photoelectric effect.’
• ‘Using Stokes' law the velocity curves were converted into force curves to obtain the relation between magnetic force and distance to the blade.’
• ‘When viewed in this way, the observed value of D, constrains the free diffusion constant D to similar values or less, about two orders or magnitude smaller than expected from Stokes' law.’
• ‘Using the data, an algorithm based on Stokes' law determines the spacing factor and specific surface of the entrained air bubbles released from the mortar sample.’
• 2An expression describing the resisting force on a particle moving through a viscous fluid and showing that a maximum velocity is reached in such cases, e.g., for an object falling under gravity through a fluid.

• ‘The air bubbles rise through the viscous liquid and the water column above it according to Stokes' law, which describes the rates at which spherically shaped particles (in this case, voids) settle (in this case, float).’
• ‘In order to investigate the dependence of the viscosity on the mass of the molecules in a liquid, and thus check the validity of Stokes' law for molecules, several molecular dynamics simulations of water molecules with different mass and different molecular mass distributions were performed.’
• ‘A drag coefficient for the bead was calculated from force/velocity (F/v) data and compared with Stokes' law to obtain the viscosity of the water, where the radius of the spherical bead is known.’

### Origin

Late 19th century: named after Sir George Stokes (1819–1903), British physicist.

/ˈstōks ˌlô/