The shape of a liquid drop becomes spherical due to

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

Consider a spherical drop of radius $R$. The surface tension of the liquid is $\sigma$. The force of surface tension on the shaded sub-hemisphere due to the remaining drop is $0.5\,\pi \sigma R$. The value of the angle $\theta$ (angle subtended by the sub-hemisphere at the center of the drop) is ......$^o$.

Why does the free surface of a liquid tend to contract?

The free surface of a liquid has a tendency to contract. This property is called ...... .

What causes the free surface of a liquid to have minimum area?