Question

Write a short note on Surface tension.

Answer 1

1. The particles in the bulk of liquid are uniformly attracted in all directions and the net force acting on the molecules present inside the bulk is zero.
2. But the molecules at the surface experience a net attractive force towards the interior of the liquid, or the forces acting on the molecules on the surface are imbalanced.
3. Therefore, liquids have a tendency to minimize their surface area and the surface acts like a stretched membrane.
4. The force acting per unit length perpendicular to the line drawn on the surface of the liquid is called surface tension.
5. Unit: Surface tension is measured in the SI unit, Nm ^–1, and is denoted by the Greek letter ‘γ’.
   
   Imbalance of forces at the surface of a liquid