Question

Given below are two statements :
Statement I : The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well.
Statement II : The rise of a liquid in a capillary tube does not depend on the inner radius of the tube.
In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are false
• B. Statement I is false but Statement II is true.
• C. Statement I is true but Statement II is false.
• D. Both Statement I and Statement II are true.

Answer 1

The Correct Option is C

Statement I: This statement is correct. The contact angle between a solid and a liquid depends on the cohesive and adhesive forces, which are properties of the materials involved.

Statement II: This statement is incorrect. The height of liquid rise in a capillary tube is given by:
\[ h = \frac{2T \cos \theta}{\rho g r}, \] where T is the surface tension, θ is the contact angle, ρ is the density of the liquid, g is the acceleration due to gravity, and r is the radius of the capillary tube. This equation shows that the height h is inversely proportional to the radius r of the tube, indicating that the rise does depend on the inner radius.

Hence, option (3) is correct.