What is the dimensions of surface …

Surface Tension

• Surface tension is the property of the liquid surface which arises due to the fact that surface molecules have extra energy.
• Surface energy is the extra energy which the molecules at the surface have.
• Surface tension is the property of the liquid surface because the molecules have extra energy.
• Surface energy is defined as surface energy per unit area of the liquid surface.
• Denoted by ’S’.
• Mathematically :-
  • Consider a case in which liquid is enclosed in a movable bar.
  • Slide the bar slightly and it moves some distance (‘d’).
  • There will be increase in the area, (dl) where l=length of the bar.
  • Liquids have two surfaces one on the bar and other above the bar. Therefore area=2(dl)
  • Work done for this change =Fxdisplacement.
  • Surface tension(S)=Surface Energy/area
  • Or Surface Energy=S x area
  • =Sx2dl
  • Therefore S x 2dl =F x d
• S = F/2d