Why is the refill of a marker pen used to write on a whiteboard made of fibers?

$A$ glass rod of radius $r_1$ is inserted symmetrically into a vertical capillary tube of radius $r_2$ $(r_1 < r_2)$ such that their lower ends are at the same level. The arrangement is dipped in water. The height to which water will rise into the tube will be ($\rho =$ density of water,$T =$ surface tension of water,$g =$ acceleration due to gravity).

$A$ capillary tube is taken from the Earth's surface to the Moon's surface. What happens to the rise of the liquid column on the Moon's surface? (Acceleration due to gravity on the Earth's surface is six times that of the Moon's surface.)

Water rises in a capillary tube kept vertically on the surface of the Earth to a height $h$. Choose the false statement regarding capillary rise from the following $:-$

Two capillary tubes made of the same material are dipped in the same liquid. If the heights of the liquid in the tubes are $2.2 \ cm$ and $6.6 \ cm$ respectively,what is the ratio of their radii?

If the rise in heights of capillary of two tubes are $6.6\,cm$ and $2.2\,cm$,then the ratio of the radii of the tubes is