Define viscosity of a liquid. Discuss factors affecting viscosity.
Answers
Temperature, pressure (at very high value) and concentration are the factors on which viscosity of a fluid depends. By increasing the temperature the viscisity of a fluid decreases fue to increase in molecular motion. Pressure doesn't have very much effect but slightly effect when high pressure is applied. Concentration has also direct relation with the viscosity.
It is well known that temperature is one of the main factors that affect the viscosity. Viscosity is getting higher as the temperature decreases. For the liquid, pressure has a very small impact on viscosity and for the gas, it has a small (not very small) impact on viscosity. But a size of the impact on the viscosity of the gases increases at high pressures. The size of molecules is also necessary to have a high or low viscous effect. For example, plastics have a high viscosity because they're made by large molecules. Moreover, in the mixtures, a fraction of each phase effects the viscosity.