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

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

$A$ 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:

The force necessary to pull a circular plate of $5\, cm$ radius from a water surface,for which the surface tension is $75\, dynes/cm$,is

Consider a water tank shown in the figure. It has one wall at $x=L$ and can be taken to be very wide in the $z$ direction. When filled with a liquid of surface tension $S$ and density $\rho$,the liquid surface makes an angle $\theta_0 \left(\theta_0 \ll 1\right)$ with the $x$-axis at $x=L$. If $y(x)$ is the height of the surface,then the equation for $y(x)$ is:
(Take $\theta(x) \approx \sin \theta(x) \approx \tan \theta(x) = \frac{dy}{dx}$,where $g$ is the acceleration due to gravity.)

$A$ wooden stick $2 \, m$ long is floating on the surface of water. The surface tension of water is $0.07 \, N/m$. By putting soap solution on one side of the stick,the surface tension is reduced to $0.06 \, N/m$. The net force on the stick will be ....... $N$.