A tank contains 1 litre of water. Water is falling drop wise from the tank. Radius of the drop is 2 mm.
If every drop takes 1 sec. to fall from the tank, then the total time required to make the tank empty is
Total amount of water = 1 litre = 1000000 cubic mm
Volume of 1 drop of water = 4*π*r*r*r/3 = 4*π*2*2*2/3 cubic mm and this drop takes 1 sec to fall from the tank
Hence total time taken = 1000000/(32*π/3) sec.
= 29856.688 sec.
= 29856.688/3600 hours
= 8.2935244 h
= 8h 17m 37s