Capillary Depression

Let h = Fall in height of liquid in tube, σ = Surface tension of liquid, and θ = Angle of contact between liquid and glass tube.

Example 9.4: Calculate the capillary rise in a glass tube of diameter 2 mm when immersed vertically in (i) water, and (ii) mercury. Assume surface tension for water as 0.07 and for mercury as 0.5 in contact with air. The specific gravity for mercury is 13.6 and angle of contact is 130°.

Solution:

Capillary rise for water at θ = 0

Capillary rise for mercury at θ = 130°