The viscous force between two liquid layers is

A ball rises to surface at a constant velocity in liquid whose density is 3 times greater than that of the material of the ball. The ratio of force of friction acting on the rising ball to its weight is

When a mercury drop of radius ' $R$ ' splits up into 1000 droplets of radius ' $r$ ', the change in surface energy is ( $T=$ surface tension of mercury)

The angle of contact between glass and water is $0^{\circ}$ and water rises in a glass capillary upto 6 cm (Surface tension of water is T). Another liquid of surface tension ' $2 \mathrm{~T}^{\prime}$ ', angle of contact $60^{\circ}$ and relative density 2 will rise in the same capillary up to $\left(\cos 0^{\circ}=1, \cos 60^{\circ}=0.5\right)$