The shape of a liquid drop becomes spherical due to

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

Give a reason why some insects are able to walk on the water surface.

On what does the value of surface tension depend? Explain.

Describe a simple experiment for the measurement of the surface tension of a liquid.