Question

Which of the following contribute to the reason behind the origin of surface tension?

• A. only cohesive forces
• B. only adhesive forces
• C. neither cohesive forces nor adhesive forces
• D. both cohesive forces and adhesive forces

Answer 1

The correct option is A

only cohesive forces

Due to the cohesive forces, a molecule inside a liquid is pulled equally in every direction by neighboring molecules, resulting in a net force of zero. But the molecules at the surface do not have any molecule above them and therefore are pulled inward by the molecules beneath them. Thus the surface behaves like a stretched elastic membrane and the tension developed at the surface is known as surface-tension.