A capillary tube is held in a vertical position with one end dipping in a liquid of surface tension γ and density ρ. If the liquid rises to a height, h, derive an expression for h in terms of γ, ρ and radius r of the tube assuming the angle of contact is zero.

The liquid rises until the vertical component of the upward forces due to surface tension is equal to the weight of the liquid column.

Fγcosθ = W but θ = 0

where:

γ – coefficient of surface tension

θ – angle of contact

r – radius of capillary tube

ρ – density of the liquid

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