Water does not wet the feathers of ducks. A physical quantity called angle of contact determines whether a liquid will spread on the surface of a solid or it will form droplets on it. Define angle of contact.

Surface tension changes with temperature. What is the value of angle of contact for pure water?

When a capillary tube of radius r is dipped in water,the water rises through it up to a height h. To what height will water rise in a glass tube with a bore of radius 0.1 mm (take the angle of contact of Glass with 0° ,surface tension is S= 0.0728 N/m )