Question

When a cylindrical tube is dipped vertically into a liquid, the angle of contact is ${140}^{\circ }$. When the tube is dipped with an inclination of ${40}^{\circ }$, the angle of contact is:

• A. ${100}^{\circ }$
• B. ${140}^{\circ }$
• C. ${180}^{\circ }$
• D. ${60}^{\circ }$

Answer 1

The correct option is B ${140}^{\circ }$

Angle of contact is a characteristic property of the interaction of a liquid with the surface in contact. It is the property of the interface formed between two phases (eg: solid & liquid).

Value of angle of contact is governed by the properties of the materials at the contact.
Hence, it does not depend on the inclination of the capillary tube.
i.e here, contact angle will be ${140}^{\circ }$ only.