Question Detail
Question
A liquid with a contact angle less 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 less than 90° indicates that adhesive forces are relatively strong. This, combined with surface tension, results in an upward force on the liquid at the walls of the tube, causing the entire liquid column to be drawn upwards, or raised, inside the capillary.
Hint
Consider the case of water in a glass tube. Its contact angle is near 0°, and you observe the water rising in the tube.