Question

What is angle of contact.. and define properly

Answer 1

Explanation: the angle between the meniscus and the containing walls of a column of liquid measured from the vertical wall below the surface of the liquid to the position of the tangent to the meniscus at its point of contact with the wall

Hope this helped !

Answer 2

Answer:

The angle of contact is the angle made by the tangent to the liquid surface at the point of contact with the solid surface inside the liquid.

★for liquids which wet the surface ϴ<90°.

★for mercury on clean glass ϴ≈135°.