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Capillary rise in a small tube dipped in water: identify the cause A narrow glass tube is dipped into water and the water rises in the tube. State whether the rise is due to viscosity or another effect.

Difficulty: Easy

Agree: rise is due to viscosity
Disagree: rise is due to surface tension and wetting (capillarity)

Correct Answer: Disagree: rise is due to surface tension and wetting (capillarity)

Explanation:

Concept/Approach

Capillary rise is caused by surface tension and the adhesive attraction between liquid and tube material, balanced by weight of the column. Viscosity influences the rate of rise, not the final height.

Final Answer
Disagree — the rise occurs due to surface tension (capillarity), not viscosity.

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