Concept:A physical system inherently attempts to minimize its potential energy. For liquids, this means minimizing surface area.
Formula:$$ \text{Sphere} = \text{Minimum Surface Area to Volume Ratio} $$
Solution:- Molecules on the surface of a liquid experience a net inward cohesive pull because there are no liquid molecules above them. This phenomenon is called Surface Tension.
- This inward force acts continuously to contract the surface boundaries.
- Geometrically, for a given volume, a sphere offers the absolute smallest possible surface area. Thus, falling free droplets naturally pull themselves into a spherical shape.
Why other options are incorrect:Viscosity resists flow but doesn't dictate equilibrium shape. Evaporation removes mass but doesn't cause spherical tension. Atomic structure determines the IMF, but Surface Tension is the direct macroscopic property responsible.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.