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

$A$ thin metal disc of radius $r$ floats on water surface and bends the surface downwards along the perimeter,making an angle $\theta$ with the vertical edge of the disc. If the weight of water displaced by the disc is $W$,the weight of the metal disc is [$T =$ surface tension of water].

$Assertion :$ $A$ large force is required to draw apart two glass plates enclosing a thin water film.
$Reason :$ Water acts as a glue and sticks the two glass plates together.

$A$ thin metal disc of radius $r$ floats on the water surface and bends the surface downwards along the perimeter,making an angle $\theta$ with the vertical edge of the disc. If the disc displaces a weight of water $W$ and the surface tension of water is $T$,then the weight of the metal disc is:

$A$ disc of paper of radius $R$ has a hole of radius $r$. It is floating on a liquid of surface tension $T$. The force of surface tension on the disc is

Soap helps in cleaning clothes,because