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

The excess pressure inside a soap bubble of radius $2.5$ cm is $48$ dyne/cm$^2$. The surface tension of soap solution in dyne /cm is