The angle of contact of a liquid in a capillary tube is `60^(@)`. The shape of the meniscus is

Options

A. Concave
B. Convex
C. Flat
D. None of these

Answer

To determine the shape of the meniscus formed by a liquid in a capillary tube given that the angle of contact is \(60^\circ\), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Angle of Contact**:
The angle of contact (or wetting angle) is defined as the angle formed between the tangent to the liquid surface at the point of contact and the tangent to the solid surface (the capillary tube) at the same point.

2. **Identify Possible Shapes of Meniscus**:
The meniscus can take three shapes based on the angle of contact:
- **Concave Meniscus**: Occurs when the liquid wets the surface well (angle < 90°).
- **Convex Meniscus**: Occurs when the liquid does not wet the surface well (angle > 90°).
- **Flat Meniscus**: Occurs when the angle of contact is exactly 90°.

3. **Analyze the Given Angle of Contact**:
In this case, the angle of contact is \(60^\circ\). Since \(60^\circ < 90^\circ\), it indicates that the liquid has a good wetting property with respect to the capillary tube.

4. **Determine the Shape of the Meniscus**:
Since the angle of contact is less than \(90^\circ\), the liquid will rise in the capillary tube and form a concave meniscus. This is because the adhesive forces between the liquid and the tube surface are stronger than the cohesive forces within the liquid.

5. **Conclusion**:
Therefore, the shape of the meniscus when the angle of contact is \(60^\circ\) is **concave**.

### Final Answer:
The shape of the meniscus is **concave**.

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