Define surface tension with its formula in the context of intermolecular forces.

(N/A) Surface tension is a property of the surface of a liquid that allows it to resist an external force,due to the cohesive nature of its molecules.
In the context of intermolecular forces,molecules at the surface experience a net inward force because they are attracted only by molecules below them,whereas molecules in the bulk are attracted equally in all directions.
This inward pull causes the surface to behave like a stretched elastic membrane.
Surface tension $(S)$ is defined as the force $(F)$ acting per unit length $(l)$ on an imaginary line drawn on the liquid surface:
$S = \frac{F}{l}$
The $SI$ unit of surface tension is $N/m$ or $J/m^2$.