Question Detail
Question
A liquid with a contact angle greater than 90° is placed in a vertical capillary tube. What will happen to the liquid level inside the tube compared to the level of the bulk liquid outside?
Correct Answer
Option B is the correct answer.
Detailed Explanation
A contact angle greater than 90° indicates that cohesive forces are relatively strong. The liquid is more attracted to itself than to the tube. Surface tension acts to flatten the convex meniscus, which results in a net downward force, suppressing (lowering) the liquid column inside the capillary.
Hint
Consider the case of mercury in a glass tube. Its contact angle is large, and you observe the mercury level in the tube is lower than the outside surface.