Molecular theory of surface tension in physics 1th
Answers
Surface tension is the property of a liquid, due to which it relaxes its free surface to behave like an elastic skin or a spreading rubber membrane with the tendency of contract to occupy the least surface area. This property is caused by the unification of the molecules and is responsible for most of the behavior of the fluid.
The properties of the surface tension have been disclosed, for example, with the ability of some objects to float on the water surface, even if they are dense with water. In order to run the surface tension on the surface of the water, some insects, such as water spiders, and even reptiles, are seen in the reptiles' capacity.
Theory behind Surface Stress
Surface tension is well explained by the molecular theory of the substance. According to this principle, the united forces between the liquid molecules are responsible for the occurrence of surface tension. Inside the liquid, the molecules are well attracted by other molecules in all directions equally. Molecules on the surface have an internal pulling experience.
Therefore, in order to move the molecule on the liquid surface, a network is formed against the inner drag. As a result, surface molecules have more potential energy. In order to obtain the minimum possible energy and therefore to obtain a steady balance, the free surface of the liquid contains the minimum surface area and thus it behaves like a stretch membrane.
Surface tension is measured on a hypothetical line drawn on a liquid-free liquid surface, per unit length, normally measured as a working force. This symbol is represented by T (or S). This is SI. The unit is NM-1 and the dimensional formula is M1L2T2.
Capillarity in fluid
When a capillary tube is immersed in the liquid, the liquid level either grows or falls into the capillary tube. The incidence of the rise or fall of a liquid level in a capillary tube is called capillary or capillary action.
How do we define the surface tension of the liquid through the capillary growth method?
When a liquid rises in a capillary tube, the weight of the column of liquid of density ρ inside the tube is supported by the upper force of surface tension acting around the perimeter of the points of contact.
Thus, surface stress;
T = (r (h + r / 3) ρg) / 2cosθ
Where the height of the liquid colmn above the liquid manscus - H
ρ-density of liquid
R-inner radius of capillary tube.
Θ-angle of contact