Question

A liquid does not wet the sides of a solid if the angle of contact is:

• A. zero
• B. obtuse (more than $90^{\circ}$)
• C. acute (less than $90^{\circ}$)
• D. $90^{\circ}$

Hint:

Acute angle = Wets the surface; Obtuse angle = Does not wet.

Answer 1

The Correct Option is B

Step 1: Concept
Wetting depends on the relative strength of cohesive and adhesive forces.
Step 2: Analysis
When cohesive forces are stronger than adhesive forces, the liquid forms droplets and does not spread.
Step 3: Conclusion
This condition results in a convex meniscus and an obtuse angle of contact.
Final Answer: (B)