A liquid drop is spherical in shape due to? & x20;

KPSC Staff Nurse - 2015

General Knowledge

Easy

A liquid drop is spherical in shape due to?

Appeared in: KPSC Staff Nurse - 2015

Surface tension is a property of liquids where the surface acts like a thin, stretched membrane.
It is caused by cohesive forces, where molecules at the surface are pulled inwards by other molecules, leading to the contraction of the surface.
This force minimizes the surface area for a given volume.
A sphere has the smallest surface area for a given volume, which is why free-falling liquid drops are spherical.

Option A: Viscosity is a measure of a fluid's resistance to flow or its 'thickness'. It does not determine the shape of a droplet.
Option B: Capillarity (or capillary action) is the ability of a liquid to flow in narrow spaces, often against gravity. It is due to both adhesive (liquid to tube) and cohesive (liquid to liquid) forces.
Option C: Buoyancy is the upward force exerted by a fluid on an object immersed in it. It explains why objects float or sink, not the shape of the fluid itself.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physical properties of liquids as background academic context rather than a clinical decision trigger.
The principle of surface tension is critical in respiratory physiology. Pulmonary surfactant, a substance produced in the lungs, reduces surface tension in the alveoli, preventing them from collapsing during exhalation.
A lack of surfactant in premature infants leads to Respiratory Distress Syndrome (RDS), where high alveolar surface tension makes breathing extremely difficult.
Surface tension also influences the formation of aerosols in nebulizers and the behavior of droplets in various laboratory tests.

How to Approach the Question

Identify the core physical phenomenon being asked about: the reason for the spherical shape of a liquid drop.
Recall the definitions of the four physical properties listed in the options.
Analyze Viscosity: This relates to flow resistance, not shape.
Analyze Capillarity: This relates to liquid movement in narrow tubes.
Analyze Buoyancy: This relates to the force on an object submerged in a fluid.
Analyze Surface Tension: This relates to the tendency of a liquid's surface to contract to the minimum possible area.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 2A p. 50-52

Practise the full KPSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.