$A$ rectangular film of liquid is expanded from $(5 \text{ cm} \times 4 \text{ cm})$ to $(7 \text{ cm} \times 8 \text{ cm})$. If the work done is $3 \times 10^{-4} \text{ J}$,the surface tension of the liquid is (nearly):

$A$ drop of some liquid of volume $0.04 \ cm^{3}$ is placed on the surface of a glass slide. Then another glass slide is placed on it in such a way that the liquid forms a thin layer of area $20 \ cm^{2}$ between the surfaces of the two slides. To separate the slides a force of $16 \times 10^{5} \ dyne$ has to be applied normal to the surfaces. The surface tension of the liquid is (in $dyne \ cm^{-1}$):

The surface tension of a liquid is $70 \, dyne/cm$. In $MKS$ system its value is

In the case of the surface of one fluid in contact with another fluid or a solid surface,what does the surface tension/surface energy depend on? Explain with an illustration.

Hairs of a shaving brush cling together when it is removed from water due to

$A$ pin or a needle floats on the surface of water,the reason for this is: