The spherical shape of a rain-drop is due to

The force required to take away a flat circular plate of radius $2 \, cm$ from the surface of water will be (the surface tension of water is $70 \, dyne/cm$).

$A$ 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:

What mass should be suspended from the wire $CD$ to keep it in equilibrium?

Small liquid drops assume a spherical shape because

At critical temperature,the surface tension of a liquid is