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

$A$ capillary tube is immersed vertically in water,and the water rises to a height $h_1$ on the Earth's surface. When this arrangement is taken into a mine of depth $d$ below the Earth's surface,the height of the water column is $h_2$. If $R$ is the radius of the Earth,the ratio $\frac{h_2}{h_1}$ is:

What is capillarity? Give two practical illustrations of capillarity.

$A$ capillary tube of radius $0.1 \,mm$ is dipped in water. The water rises to a height of $2 \,cm$ in the tube. If the surface tension of water is $0.072 \,N/m$, the contact angle between water and the wall of the tube is:

In a capillary tube having area of cross-section $A$,the water rises to a height $h$. If the cross-sectional area is reduced to $\frac{A}{9}$,the rise of water in the capillary tube is

The kerosene oil rises up in the wick of a lamp ...........