Solved: PHYSICS Question for NEET

NEET PHYSICSEasy

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

surface tension.

density.

angle of contact between the surface and the liquid.

viscosity.

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.
Angle of Contact: The angle of contact ( $\theta$ ) is the angle formed between the tangent to the liquid surface at the point of contact and the solid surface, measured inside the liquid .
Dependence:

If the angle of contact is acute ( $\theta < 90^\circ$ ), the liquid spreads and wets the surface (e.g., water on glass).
If the angle of contact is obtuse ( $\theta > 90^\circ$ ), the liquid tends to form droplets and does not wet the surface (e.g., mercury on glass or water on a lotus leaf) .

Conclusion: Therefore, the wettability is directly determined by the value of the angle of contact.

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