At critical temperature,the surface tension of a liquid is

The shape of a liquid drop becomes spherical due to

With an increase in temperature,surface tension of liquid (except molten copper and cadmium)

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

$n$ number of liquid drops each of radius $r$ coalesce to form a single drop of radius $R$. The energy released in the process is converted into the kinetic energy of the big drop so formed. The speed of the big drop is [$T = \text{surface tension of liquid}, \rho = \text{density of liquid}$.]

The force required to take away a flat circular plate of radius $2 \, cm$ from the surface of water will be (the surface tension of water is $70 \, dyne/cm$).