The liquid drops or gas bubbles are always spherical due to?

Appeared in: BCCL kharkhanda Staff Nurse - 2015

Explanation

Surface tension is a property of liquids where the surface layer behaves like a stretched elastic membrane.
It is caused by the cohesive forces between liquid molecules. Molecules at the surface experience a net inward pull because they have fewer neighboring molecules above them.
This inward force minimizes the surface area of the liquid to the smallest possible size for a given volume.
Geometrically, a sphere is the shape that has the minimum surface area for a given volume, which is why drops and bubbles are spherical.

Option A: 'Volume tension' is not a recognized term in physics to explain this phenomenon.
Option C: Gravitational force acts on the mass of the liquid, pulling it downward, and can cause distortion (flattening) in larger drops, but it does not create the spherical shape itself.
Option D: Magnetic force only affects materials that are magnetic. Most common liquids, such as water, are not magnetic.

Clinical Relevance

Nursing practice connection: Knowing Surface Tension helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
The concept of surface tension is vital in respiratory physiology. The alveoli in the lungs are lined with a fluid that exerts surface tension, creating a tendency for them to collapse.
The body produces pulmonary surfactant, a substance that dramatically reduces this surface tension, preventing alveolar collapse (atelectasis) and reducing the work of breathing.
What if? A premature infant is born without adequate surfactant production. This leads to Infant Respiratory Distress Syndrome (IRDS), where the high alveolar surface tension makes breathing extremely difficult and can be fatal without treatment like mechanical ventilation and administration of artificial surfactant.

How to Approach the Question

Identify the core physical principle the question is asking about: the cause of the spherical shape of liquid drops.
Analyze the options based on fundamental physics concepts related to liquids and forces.
Recall that 'surface tension' is the property of a liquid that causes it to acquire the least surface area possible. A sphere has the minimum surface area for a given volume.
Eliminate 'Volume tension' as it is not a standard scientific term.
Rule out 'Gravitational force' as the primary cause of the shape, although it can distort it.
Rule out 'Magnetic force' as it is not applicable to most common liquids.

Concept Tested & Keywords

QD2toDiSR7YB-ghMSTcv-6

E6 Physiology Guyton 4SAE Part 2A pp. 50-52, 49-51

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