# The property of fluid which offers resistance to the movement of one layer of fluid over another layer of fluid, is called:

36 views
in General
closed
The property of fluid which offers resistance to the movement of one layer of fluid over another layer of fluid, is called:
1. fluidity
2. viscosity
3. specific weight
4. turbidity

by (110k points)
selected

Correct Answer - Option 2 : 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 as 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 air. The measurement of turbidity is a key test of water quality.