Thiruvalluvar University Vellore Question Paper

Explanation:
A thin metallic object placed gently on a liquid surface can sometimes remain supported even though it is denser than the liquid itself. This situation depends on how the liquid surface behaves when it is not disturbed. The outer layer of a liquid acts like a stretched membrane because molecules at the surface experience unbalanced forces compared to those inside the liquid. When an object is carefully placed, it does not immediately break this surface layer. Instead, the surface bends slightly and distributes the load along the curved interface. This balance between the downward force due to weight and the upward support from the stretched liquid surface allows temporary equilibrium. The stability of this effect also depends on how clean the surface is, the shape of the object, and how gently it is placed. Even a small disturbance can disrupt this balance and cause the object to sink.

Explanation:
Small fragments placed on a still liquid surface sometimes show spontaneous motion without any external push. This happens because the surface of the liquid is not uniform everywhere. Variations in local conditions around the floating material create differences in how strongly the surface pulls inward at different points. These differences produce unbalanced forces along the surface, leading to motion in various directions. As the material slowly dissolves or releases molecules into the surrounding liquid, the local Environment keeps changing, which continuously disturbs equilibrium. The result is irregular movement patterns such as spinning, drifting, or sudden shifts. This phenomenon is commonly used to demonstrate how sensitive liquid surfaces are to slight chemical or physical changes occurring at the interface.

Explanation:
Flowing liquids resist motion due to internal friction between their layers. This internal resistance depends on how strongly one layer of Fluid drags another while moving. To describe this property scientifically, a special measurable quantity is defined, and it requires a standard unit. The measurement is based on how much force is needed to maintain a steady flow between two parallel layers of liquid when one layer moves relative to the other. In experiments, a liquid is placed between surfaces and allowed to move under controlled conditions so that resistance can be calculated. The unit used for expressing this resistance comes from classical Fluid mechanics and is commonly applied in laboratory measurements involving thick liquids like oils, honey, and syrups. This helps compare how easily different liquids flow under the same conditions and is important in industries like lubrication, chemical processing, and Food production where flow behavior matters significantly.

Explanation:
Gravitational strength depends on the Mass and radius of a celestial body. Larger and more massive bodies produce stronger gravitational pull on objects near their surface. When comparing two different astronomical bodies, their surface gravity is evaluated by analyzing how strongly each one attracts the same object. This comparison is often expressed as a ratio to understand relative strength rather than absolute values. The Moon has significantly less Mass and a smaller size compared to Earth, resulting in weaker attraction on objects. Because of this difference, an object would weigh much less on the Moon than on Earth. The relationship is widely used in space science to understand motion of satellites, astronauts’ weight differences, and planetary exploration conditions.

Explanation:
When a Solid object such as a spring or wire is stretched or compressed, it tends to return to its original shape once the external force is removed. This behavior is known as elasticity. The relationship between the applied force and the resulting deformation is proportional within a certain limit, meaning greater force produces greater extension. This proportional behavior continues until the material reaches its elastic limit, beyond which permanent deformation occurs. This principle is widely used in mechanical systems like spring balances, shock absorbers, and measuring instruments. It helps describe how materials respond to stress and strain under controlled conditions. The study of this behavior is fundamental in understanding material strength and mechanical stability in engineering and Physics applications.

Explanation:
When two liquids are placed together, they arrange themselves based on differences in their physical properties, especially how much Mass is packed into a given volume. This property determines whether a substance tends to rise or settle when placed in another Fluid. Liquids with lower compactness tend to occupy the upper layer, while those with higher compactness settle lower. In mixtures where liquids do not mix easily, they form separate layers instead of combining. The arrangement depends on how each liquid interacts internally and with surrounding molecules. This layering effect is commonly observed in everyday situations such as cooking or natural water systems. The stability of these layers is influenced by intermolecular forces and resistance to mixing.

Explanation:
Small liquid droplets naturally tend to adopt a shape that minimizes their overall surface area. This behavior is driven by the cohesive forces between molecules at the surface, which pull inward equally from all directions. As a result, the liquid contracts into the most efficient geometry that reduces exposed surface energy. In free fall, additional forces act on the droplet, but surface behavior remains dominant for small sizes. The surrounding air exerts minimal distortion when compared to the internal cohesive forces, allowing the droplet to maintain a smooth curved boundary. This balance of forces creates a stable, rounded form that is commonly observed in nature during rainfall and mist formation. The same principle explains why many small liquid droplets behave similarly in other environments as well.