'$$n$$' 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
$$[\mathrm{T}=$$ surface tension of liquid, $$\rho=$$ density of liquid.]
At critical temperature, the surface tension of liquid is
A metal sphere of mass '$$m$$' and density '$$\sigma_1$$' falls with terminal velocity through a container containing liquid. The density of liquid is '$$\sigma_2$$'. The viscous force acting on the sphere is
Water flows through a horizontal pipe at a speed '$$\mathrm{V}$$'. Internal diameter of the pipe is '$$\mathrm{d}$$'. If the water is coming out at a speed '$$V_1$$' then the diameter of the nozzle is