2. Student name 1.Devarshi Pandya 2.Karan Patel 3.Manank Patel Enrollment number 130460106040 130460106056 130460106059

4. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.

5. Surface tension can be defined as tensile force acting on the free surface of a liquid per unit length.

6. for example, any type an object that is denser than water is able to float or run along the water surface

7. This phenomenon explains about the surface tension Consider the 3 molecules of the liquid. The molecule 1 is attracted in all directions

8. Thus the resultant forces acting on a molecule 1 is zero. But 2 molecule which is situated near the free surface is acted upon upward & downward directions.

9. The molecule 3 situated on the free surface of liquid is subjected only net resultant downward force  Thus,the free surface of liquid acts like a very thin layer under tension on the surface of liquid

10. Consider a small liquid drop of radius ‘r’.  P= pressure intensity in side drop.  d=diameter of droplet.  = surface tension of liquid.

11. The force acting on half drop  Tensile force acting around the circumference of cut portion  Tensile force= x d

12. Pressure force on area  Pressure force on area = /4 x =p x /4 x Under equilibrium conditions, these 2 forces will be equal & opposite

13. Pressure force on area p x /4 x = x p=4 /

14. The surface tension depends directly upon the intermolecular cohesion,& since this cohesion is known to decrease with temperature rise, tension decrease

15. The surface tension of water varies from about 0.074 N/m At 20 C to 0.0589 N/m at 100 C.The surface tension of some liquids at 20 C at atmospheric pressure are given below

16. liquidN/m Kerosene0.0277 Glycerine0.0633 Benzene0.0289 mercury0.514

17. Thin blade or clip float on the surface of water.

18. Mercury on smooth surface converts in to small balls

19. Rain water comes to the earth surface in the form of circular balls.

20. Rain water falls on the leaf it form circular balls.