Define surface tension and provide its formula in the context of $(i)$ intermolecular forces,$(ii)$ potential energy,and $(iii)$ work done.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Surface tension is a property of the liquid surface that allows it to resist an external force,due to the cohesive nature of its molecules.
$(i)$ In terms of intermolecular forces: Surface tension is defined as the force per unit length acting on an imaginary line drawn on the free surface of a liquid,perpendicular to the line and parallel to the surface. If $F$ is the force acting on a line of length $l$,then surface tension $S$ is given by:
$S = \frac{F}{l} \left( \frac{\text{N}}{\text{m}} \right)$
$(ii)$ In terms of potential energy: Surface tension is defined as the potential energy stored per unit area of the free surface of a liquid. If $E$ is the potential energy and $A$ is the area,then:
$S = \frac{E}{A} \left( \frac{\text{J}}{\text{m}^2} = \frac{\text{N} \cdot \text{m}}{\text{m}^2} = \frac{\text{N}}{\text{m}} \right)$
$(iii)$ In terms of work done: Surface tension is defined as the work done per unit increase in the surface area of a liquid. If $W$ is the work done to increase the area by $\Delta A$,then:
$S = \frac{W}{\Delta A} \left( \frac{\text{J}}{\text{m}^2} = \frac{\text{N}}{\text{m}} \right)$

Explore More

Similar Questions

$A$ thin metal disc of radius $r$ floats on water surface and bends the surface downwards along the perimeter,making an angle $\theta$ with the vertical edge of the disc. If the weight of water displaced by the disc is $W$,the weight of the metal disc is [$T =$ surface tension of water].

If the surface area of the soap solution is increased,then its surface tension

If the work done in increasing the size of a soap film from $10\, cm \times 6\, cm$ to $60\, cm \times 11\, cm$ is $2 \times 10^{-4}\, J$,what is the surface tension?

Difficult
View Solution

The unit of surface tension in the $SI$ system is

Consider a circular ring of radius $1.4 \,cm$ lying on the surface of a liquid. If a vertical force of $0.022 \,N$ greater than the weight of the ring is required to lift this ring from the liquid surface,then the surface tension of the liquid is (in $\,Nm^{-1}$)

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo