$A$ thin liquid film formed between a $U$-shaped wire and a light slider supports a weight of $1.5 \times 10^{-2} \; N$ (see figure). The length of the slider is $30 \; cm$ and its weight is negligible. The surface tension of the liquid film is (in $; N m^{-1}$)

$A$ steel coin of thickness $d$ and density $\rho$ is floating on water of surface tension $T$. The radius of the coin $R$ is [ $g$ = acceleration due to gravity]

In the case of the surface of one fluid in contact with another fluid or a solid surface,what does the surface tension/surface energy depend on? Explain with an illustration.

Why are small drops of liquid spherical in shape?

When water is heated,bubbles form at the bottom and detach to rise. Let the radius of the bubble be $R$. The bubble is in circular contact with the bottom of the container with a radius $r$. If $r \ll R$ and the surface tension of water is $T$,find the value of $r$ just before the bubble detaches from the container. (Density of water is $\rho_w$)

What is the ratio of the surface tension force acting on the curved part to that on the flat part?