Correct Answer - Option 4 : Viscosity
Explanation:
Viscosity:
- When a fluid moves relative to a solid or when two fluids move relative to each other. The property that represents the internal resistance of a fluid to motion (i.e. fluidity) is called viscosity.
- The fluids for which the rate of deformation is proportional to the shear stress are called Newtonian fluids and the linear relationship for a one-dimensional system is shown in the figure. The shear stress(τ ) is then expressed as,
\({\rm{\tau }} = {\rm{\mu }}\frac{{{\rm{du}}}}{{{\rm{dy}}}}\) ;
- where \( \frac{{{\rm{du}}}}{{{\rm{dy}}}}\) is the shear strain rate and µ is the dynamic (or absolute) viscosity of the fluid.
- The dynamic viscosity has the dimension ML-1T-1 and the unit of kg/m.s or, \((N-sec)/m^2 \) or Pa-s. A common unit of dynamic viscosity is Poise which is equivalent to 0.1 Pa.s.
Kinematic viscosity (ν):
- The ratio of dynamic viscosity (µ ) to density (ρ).
- \(υ =μ/ρ\) ; It has got the dimension of L2T-1 and unit of stoke (1 stoke = 0.0001 m2/s).
Fluidity: The ability of a substance to flow easily.
Specific weight(ω): weight per unit volume of the substance is called specific weight. (ω = ρg)
Turbidity: Turbidity is the cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye, similar to smoke in the air. The measurement of turbidity is a key test of water quality.
