Question

If ‘θ’ represents the angle of contact made by a liquid which completely wets the surface of the container then ..........

• A. \(\theta = 0\)
• B. \(0 < \theta < \dfrac{\pi}{2}\)
• C. \(\theta = \dfrac{\pi}{2}\)
• D. \( \theta = \pi\)

Hint:

When a liquid completely wets a surface, the angle of contact is zero.

Answer 1

The Correct Option is A

Step 1: Angle of contact.
The angle of contact is defined as the angle between the tangent to the liquid surface and the surface of the solid. If the liquid completely wets the container, the angle of contact is zero.
Step 2: Analyzing the options.

- (1) \(\theta = 0\): Correct. If the liquid completely wets the surface, the angle of contact is zero.
- (2) \(0 < \theta < \dfrac{\pi}{2}\): Incorrect. This would occur for partial wetting.
- (3) \(\theta = \dfrac{\pi}{2}\): Incorrect. This corresponds to no wetting.
- (4) \(\theta = \pi\): Incorrect. This would correspond to reverse wetting.

Step 3: Conclusion.
The correct answer is \(\theta = 0\), corresponding to option (1).