ANGLE OF CONTACT

 ANGLE OF CONTACT

The angle of contact between a liquid and a solid is defined as the angle enclosed between the tangent to the liquid surface and the solid surface which is in contact the liquid as show in the figure  given below 

 The angle of contact varies between 0° to 180°.

For the liquids which wet the surface of solid (such as water and glass), the angle of contact is acute, while those for liquids which do not wet the surface of solid (such as mercury and glass), the angle of contact is obtuse.

Angle of contact decreases with the addition of impurities whereas it increases if temperature is increased.