Question

The rise of a liquid in a capillary tube depends on:

• A. the material.
• B. the length.
• C. the outer radius.
• D. the inner radius of the tube.

Answer 1

Answer: (A), (B), (D)

the length.
the material.
the inner radius of the tube.

The height $h$ through which a liquid will rise in a capillary tube of inner radius $r$ is given by
$h=\frac{2S\cos \theta }{r\rho g}$
Where $S$ is the surface tension, $\rho$ is the density of the liquid and $\theta$ is the angle of contact.
We see that rise of the liquid in capillary tube depends upon the angle of contact and angle of contact is property of both solid and liquid. So option 'A' is correct.
Although the length is not directly into the formula of rise of the liquid. that doesnt mean that liquid can rise to infinite length. The liquid will rise to maximum length available, but will never overflow. So option 'B' is also correct.
It is independent of outer radius. So option C is incorrect.
And it is inversely proportional to inner radius of capillary as shown by formula. So option D is correct.