Which of the graphs below could represent the relationship between...

The capillary rise $h$ in a tube of radius $r$ is given by Jurin's law:

$h = \dfrac{2T \cos \theta}{\rho g r}$

where $T$ is the surface tension, $\theta$ is the contact angle, $\rho$ is the density of the liquid, and $g$ is the acceleration due to gravity.

For a given liquid and capillary tube material, the terms $T$, $\theta$, $\rho$, and $g$ are constant. Thus, the relationship between $h$ and $r$ is:

$h \propto \dfrac{1}{r}$

This indicates that $h$ is inversely proportional to $r$, and the equation $hr = \text{constant}$ represents a rectangular hyperbola.

Looking at the given graphs, curve 'c' is a rectangular hyperbola, which correctly represents this inverse relationship.