The wettability of a surface by a liquid depends primarily on:

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Accepted Answer

1. **Concept of Wettability:** Wettability refers to the ability of a liquid to spread on a solid surface. This phenomenon is governed by the interaction energies between the solid, liquid, and air interfaces.
2. **Angle of Contact:** The angle of contact ($	heta$) is the angle formed between the tangent to the liquid surface at the point of contact and the solid surface, measured inside the liquid .
3. **Dependence:** 
   - If the angle of contact is acute ($	heta < 90^\circ$), the liquid spreads and **wets** the surface (e.g., water on glass).
   - If the angle of contact is obtuse ($	heta > 90^\circ$), the liquid tends to form droplets and does **not wet** the surface (e.g., mercury on glass or water on a lotus leaf) .
4. **Conclusion:** Therefore, the wettability is directly determined by the value of the angle of contact.

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