Correct Answer - Option 4 : Compressibility
Explanation:
Tenacity:
The tenacity of a body is represented by the greatest longitudinal stress per unit of cross section that it can bear without rupture.
Plasticity:
It is the property of material to undergo a non-reversible change of shape in response to an applied force.
Viscosity:
The property which opposes the relative motion between two adjacent layers in a fluid is known as viscosity.
Compressibility (α):
It is the measure of the change in volume or density of matter under the application of pressure. It is given as an inverse of the bulk modulus.
\({\rm{\alpha }} = \frac{1}{{\rm{K}}}\)
Bulk modulus (K):
It is the measure of pressure required to create a change in volume per initial volume.
\({\rm{K}} = \frac{{ - {\rm{dp}}}}{{\frac{{{\rm{dv}}}}{{\rm{v}}}}}\)
The minus sign indicates a decrease in the volume of fluid
Thus the answer is compressibility.
Compressible and incompressible flow:
The compressibility of flow is decided based on volumetric strain and not on bulk modulus
\(\frac{{{\rm{dV}}}}{{\rm{V}}} \le 0.05,{\rm{then\ the\ flow\ is\ incompressible}}\)
\(\frac{{{\rm{dV}}}}{{\rm{V}}} > 0.05,\;{\rm{then\ the\ flow\ is\ compressible}}\)
