The free surface of a liquid has a tendency to contract. This property is called ...... .

It is better to wash clothes in hot water than in cold water. Explain.

How does the surface tension of a liquid change with temperature?

$A$ liquid is coming out from a vertical tube. The relation between the weight of the drop $W$,surface tension of the liquid $T$,and radius of the tube $r$ is given by,if the angle of contact is zero.

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 $\rho_w$)

The surface tension of $70 \text{ dynes/cm}$ is equal to: