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Work done In changing the area of Surface Film

 A film on the surface of a liquid as a surface tension, which is a property of the liquid and the surroundings. The surface tension acts to make the surface area of the liquid a minimum. It has the unit of force per length. the work done on a homogenous liquid film in a changing its surface area by an infinitesimal amount dA is 




dW = - # dA 

where # ( sigma ) is the surface tension ( N/m ). 

W = - Integral ( 2 to 1) # dA.

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