A small piece of wire 4cm long, is floating on surface of water. If a force of 560 dynes in excess of its weight is required to pull it up from the surface, find the surface tension of water.

A small piece of wire 4cm long, is floating on surface of water. If a

1.	A small piece of wire 4cm long, is floating on surface of water. If a force of 560 dynes in excess of its weight is required to pull it up from the surface, find the surface tension of water.
Answer» Solution :Length of wire L = 4 cm Contact length of solid with liquid surface L = 2l = 8 cm `therefore` surface tension force F= 560 DYNES Surface tension `T=F/LrArrT=560/8=70` DYNE/cm Surface tension of water = 70 dyne `cm^(-1)=0.07Nm^(-1)`. The force REQUIRED, F = T(L) = `0.08xx1.32,F=0.1056N`.