When a big drop of water is formed from n small drops of water, the energy loss is 4 E , where E is the energy of the bigger drop. If $R$ and $r$ is the radius of the bigger and the smaller drop respectively then number of smaller drops $n$ is

Two solid spheres of same material but of mass ' M ' and ' 8 M ' fall simultaneously through a viscous liquid. Their terminal velocities are respectively ' V ' and ' nV '. The value ' n ' is

A small steel ball of mass ' M ', radius ' R ' and density ' $\rho$ ' falls with terminal velocity through a tube filled with glycerine of density ' $\sigma$ '. The viscous force acting on the steel ball is ( $\mathrm{g}=$ acceleration due to gravity)

If the shape of the liquid surface is curved, then the