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

Soap solution is used for cleaning dirty clothes because

$A$ thin metal disc of radius $r$ floats on the water surface and bends the surface downwards along the perimeter,making an angle $\theta$ with the vertical edge of the disc. If the disc displaces a weight of water $W$ and the surface tension of water is $T$,then the weight of the metal disc is:

$A$ soap film of surface tension $3 \times 10^{-2} \, N/m$ is formed in a rectangular frame and can support a straw. The length of the film is $10 \, cm$. The mass of the straw the film can support is ........ $g$.

What tendency do molecules on the surface of a liquid possess?

$A$ spherical body of density $\rho$ is floating half immersed in a liquid of density $d$. If $\sigma$ is the surface tension of the liquid,then the diameter of the body is