NEET Physics Question - Solid and Fluids - Surface Tension and Viscosity

Assertion (A): The angle of contact of a liquid decreases with increase in temperature.

Reason (R): With increase in temperature, the surface tension of liquid increases.

(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)

(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(3) (A) is true but (R) is false

(4) Both (A) and (R) are false

Solution:

Concept: Effect of temperature on liquid properties. Assertion (A) is true; generally, the angle of contact decreases with increasing temperature as intermolecular forces weaken. Reason (R) is false; surface tension of a liquid *decreases* with an increase in temperature, not increases, because the kinetic energy of molecules increases, reducing cohesive forces.

Rankers Physics

Angle of Contact and Surface Tension

Solution:

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