To what physical property is the surface energy per unit area numerically equivalent _____________________?
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Answer: B. surface tension
Explanation
Surface energy per unit area is numerically and dimensionally equivalent to surface tension in liquid interfaces. Work required to increase the surface area of a liquid against molecular forces equals the product of surface tension and area change. Both physical properties quantify the inward cohesive forces acting on molecules located at the boundary of a liquid. Surface tension arises because interior liquid molecules experience balanced cohesive forces, while surface molecules experience net inward pulls. Surface energy represents the excess potential energy experienced by molecules residing at the surface compared to the bulk liquid. Dimensional analysis confirms that surface tension has units of force per length, identical to energy per area.
Atmospheric pressure measures the force exerted per unit area by the surrounding air column rather than liquid surface energy. Force of adhesion describes dissimilar molecular attraction rather than the self-cohesive surface energy of a pure liquid. Viscosity measures a fluid resistance to gradual deformation by shear or tensile stress rather than static surface energy.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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