MCQ Detailed View

Blotting paper is a type of highly absorbent paper used to soak up excess liquids. The scientific principle behind this absorption is known as capillary action. Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, and sometimes against, external forces like gravity.

The structure of blotting paper is made of tiny, porous fibers with narrow spaces between them. When a drop of liquid touches the paper, the molecules at the edge of the drop are attracted to the molecules of the paper through a force called adhesion. At the same time, cohesion — the attraction between liquid molecules — helps pull more liquid into the tiny spaces. This combination of forces causes the liquid to “climb” or spread through the paper.

This is the same principle that allows water to rise through the roots and stems of plants. In both cases, capillary action moves the fluid upward through tiny passages due to intermolecular forces. Capillary action is also observed in thin tubes, cloth, and sponges.

Other options like surface action or boldness are incorrect. “Surface action” is not a standard scientific term, and “boldness” has no relevance in physics. While “viscosity” does affect the rate at which a liquid moves, it is not the driving force behind blotting paper absorption.

Capillary action is a fundamental topic in Physics, particularly in fluid mechanics and surface tension. It helps explain various everyday phenomena, such as how ink moves in fountain pens, how towels soak up water, and how liquids behave in confined spaces.

Understanding this principle provides insight into both natural systems and man-made materials that rely on efficient liquid absorption.

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