$A$ square frame of each side $L$ is dipped in a soap solution and taken out. The force acting on the film formed is ($T =$ surface tension of soap solution). (in $TL$)

The shape of a liquid drop becomes spherical due to

If the surface area of the soap solution is increased,then its surface tension

$A$ 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 ....... $N$.

Soap solution is used for cleaning dirty clothes because

When water is filled carefully in a glass,one can fill it to a height $h$ above the rim of the glass due to the surface tension of water. To calculate $h$ just before water starts flowing,model the shape of the water above the rim as a disc of thickness $h$ having semicircular edges,as shown schematically in the figure. When the pressure of water at the bottom of this disc exceeds what can be withstood due to the surface tension,the water surface breaks near the rim and water starts flowing from there. If the density of water,its surface tension and the acceleration due to gravity are $10^3 \ kg \ m^{-3}$,$0.07 \ N \ m^{-1}$ and $10 \ m \ s^{-2}$,respectively,the value of $h$ (in $mm$) is: