Question

If a capillary experiment is performed in a vacuum, what will happen to the liquid in the capillary tube?

Options

• Rise

• Remain the same

• Fall

• Rise to the top

Answer 1

Rise to the top

Explanation:

The capillary rise formula is h = \[\frac {\text {2σ cos ⁡θ}}{\text {ρgr}}\]​. In a vacuum, there is no air pressure acting on the liquid surface outside the tube. This means there is no downward atmospheric pressure to oppose the rise, so the liquid rises all the way to the top of the capillary tube due to surface tension alone.