Question

The capillary action tendency of a liquid is a consequence of:

• A. Osmosis
• B. Vapour Pressure
• C. Viscosity
• D. Surface tension

Hint:

Capillary rise $h$ is directly proportional to surface tension $T$ ($h = \frac{2T \cos \theta}{r \rho g}$). No tension, no rise!

Answer 1

The Correct Option is D

Step 1: Concept Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.

Step 2: Meaning It occurs because of intermolecular forces between the liquid and surrounding solid surfaces (adhesion) and among the liquid molecules themselves (cohesion).

Step 3: Analysis Surface tension is the result of cohesive forces. The imbalance of forces at the surface creates a "film" effect. When adhesive forces to a tube wall are stronger than cohesive forces, the surface tension pulls the liquid up.

Step 4: Conclusion Therefore, capillary rise or depression is fundamentally a direct consequence of the surface tension of the liquid. Final Answer: (D)