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

$A$ soap film of surface tension $3 \times 10^{-2} \, N/m$ is formed in a rectangular frame and can support a straw. The length of the film is $10 \, cm$. The mass of the straw the film can support is ........ $g$.

When there is no external force,the shape of a liquid drop is determined by

$A$ paper disc of radius $R$ from which a circular hole of radius $r$ is cut out,is floating in a liquid of surface tension $T$. The force on the disc due to surface tension will be

$A$ wire of length $10 \text{ cm}$ is gently placed horizontally on the surface of water having surface tension of $75 \times 10^{-3} \text{ N/m}$. What force is required to just pull up the wire from the water surface?

The temperature at which the surface tension of water is zero is: