$A$ square frame of side $L$ is dipped in a liquid. On taking out,a membrane is formed. If the surface tension of the liquid is $T$,the force acting on the frame will be (in $TL$)

On what factors does the value of surface tension depend? Explain.

$A$ drop of some liquid of volume $0.04 \ cm^{3}$ is placed on the surface of a glass slide. Then another glass slide is placed on it in such a way that the liquid forms a thin layer of area $20 \ cm^{2}$ between the surfaces of the two slides. To separate the slides a force of $16 \times 10^{5} \ dyne$ has to be applied normal to the surfaces. The surface tension of the liquid is (in $dyne \ cm^{-1}$):

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

$A$ thread is tied slightly loose to a wire frame as shown in the figure. The frame is dipped into a soap solution and taken out,such that the frame is completely covered with a soap film. When the portion $A$ is punctured with a pin,the thread:

On mixing salt in water,the surface tension of water will: