Question

define surface tension.
:-
the force per unit length acting at right angles to an imaginary line drawn on the free surface of liquid is called surface tension ​

Answer 1

Answer:

Surface tension is the tendency of fluid surfaces to shrink into the minimum surface area possible. Surface tension allows insects (e.g. water striders), usually denser than water, to float and slide on a water surface.

Surface tension is the tendency of fluid surfaces to shrink into the minimum surface area possible. Surface tension allows insects (e.g. water striders), usually denser than water, to float and slide on a water surface.At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion). The net effect is an inward force at its surface that causes the liquid to behave as if its surface were covered with a stretched elastic membrane. Thus, the surface comes under tension from the imbalanced forces, which is probably where the term "surface tension" came from.Because of the relatively high attraction of water molecules to each other through a web of hydrogen bonds, water has a higher surface tension (72.8 millinewtons per meter at 20 °C) than most other liquids. Surface tension is an important factor in the phenomenon of capillarity.Surface tension has the dimension of force per unit length, or of energy per unit area. The two are equivalent, but when referring to energy per unit of area, it is common to use the term surface energy, which is a more general term in the sense that it applies also to solids.In materials science, surface tension is used for either surface stress or surface energy.

Answer 2

Answer:

Surface tension is defined as the amount of force exerted in the surface perpendicular to a line of unit length.

Explanation:

Surface tension is the property of liquid surfaces, acting as if they were a stretched elastic membrane.

• Depends mainly upon the forces acting between the particles of liquid and also the particles in contact with it.
• Molecules inside the liquid drop are attracted equally in all directions by the surrounding molecules.
• If surface molecules are displaced slightly outward from the surface, they are attracted back by the nearby molecules.
• So, surface tension is the result of forces acting in the plane of the surface and tending to minimize its area.
• Therefore,  surface tension is defined as the amount of force exerted in the surface perpendicular to a line of unit length.
• Units are joules/ square meters or newtons per meter.
• Increase in temperature lowers the net force of attraction between the molecules and hence decreases surface tension.