The property by which a liquid opposes relative motion between its different layers is called:
Try it first: pick an option, then read the explanation.
Correct answer: C. viscosity
Asked in SSC JE 2 MARCH 2017 Evening Shift
Detailed Explanation
When adjacent layers of fluid move at different velocities, an internal shearing resistance arises. The physical property responsible for this internal fluid friction is viscosity.
Why “viscosity” Is Correct
Viscosity is the fundamental fluid property that determines resistance to shearing stresses and opposes relative motion between adjacent layers.
Why the Other Options Are Wrong
- A. surface tension: Surface tension is an interfacial phenomenon causing liquid surfaces to contract.
- B. co-efficient of viscosity: Coefficient of viscosity is the quantitative numerical measure (μ), whereas the property itself is viscosity.
- D. osmosis: Osmosis is the spontaneous passage of solvent molecules across a semipermeable membrane.
Key Point
Viscosity is the property by which a fluid resists relative motion between its adjacent layers.
Key Concepts for Students
- Analogous to friction between sliding solid surfaces.
- Dynamic viscosity μ is the quantitative measure of this resistance.
- Shear stress τ = μ(du/dy).
Practice more: this is question 57 in Properties of Fluid MCQs – Part 4. Try the whole set and check every answer instantly.