Basic Property – Volume change with pressure The variation of the volume of a liquid with variation of pressure is defined as its what property?

Introduction:
Continuum mechanics distinguishes between properties governing shape change under shear (viscosity) and volume change under pressure (compressibility). This question asks for the term that specifically quantifies how a liquid volume changes with pressure.

Given Data / Assumptions:

• Isotropic liquid at standard temperature and moderate pressures.
• Small, reversible volumetric changes under pressure increments.
• No phase change or cavitation.

Concept / Approach:

Compressibility is defined as beta = − (1 / V) * (dV / dP), the fractional change in volume per unit increase in pressure. Its reciprocal K = 1 / beta is the bulk modulus of elasticity. For most engineering calculations with water at modest pressures, compressibility is small and the flow may be modeled as incompressible, but in transients and acoustics, finite compressibility is essential.

Step-by-Step Solution:

Verification / Alternative check:

Standard fluid property tables list compressibility and bulk modulus for liquids; water’s bulk modulus is about 2 * 10^9 Pa at room temperature, implying small volume changes for moderate pressure variations.

Why Other Options Are Wrong:

Surface tension: Relates to interface energy and curvature, not bulk volume change.Capillarity: Phenomenon arising from surface tension in small tubes.Viscosity: Measures resistance to shear deformation, not volume change.Elastic modulus of rigidity: Pertains to solids under shear, not fluids under pressure.

Common Pitfalls:

Assuming “incompressible” means zero compressibility; it means volume change is negligible for the application, not mathematically zero.

Final Answer:

compressibility