Wednesday, 27 April 2016

Surface tension and Surface energy

Its is the property of any type of liquid by virtue of which it try to minimize its surface area.
it is measured force acting on imaginary line per unit length that is drown tangential to the free surface of liquid

Mathematically given as
S = F/L = (work done)/(change in area)

It is scalar quantity
Surface tension is the molecular phenomenon cause due to cohesive force.

Surface tension of
liquid depend upon

  • Only Nature of liquid 

Surface tension of liquid is independent upon
  • The surface area of film  
Molecular Range 

the maximum distance upto which a molecule can exert a force of attraction or repulsion on other molecule is called molecular range

In solid and liquid it is of the order of 10^-9 m .

Surface energy

On increasing the free surface area of liquid ,work has to be done against the force of tension .
this work done stored in liquid surface as a potential energy .

This Additional potential energy per unit area of free surface of liquid is called surface energy.

surface energy = surface tension * increase in surface area .