If we dip capillary tubes of different radii $r_n$ in water and the water rises to different heights $h_n$ in them, then ($n = 1, 2, 3$ .........)

A small metal sphere is falling through a viscous liquid. The variation of velocity ($V$) with time ($t$) is shown correctly in graph

On opposite sides of a wide vertical vessel filled with water (density $\rho$), two identical holes are drilled, each having cross-section area $A$. The height difference between holes is $x$. The resultant force of reaction of water flowing out of vessel is ($g$ = acceleration due to gravity)

If $450$ erg of work is done in blowing a soap bubble of radius '$r$', the additional work required to be done to blow it to a radius equal to $3r$ is