How does an oil lamp produce light through a wick that is lit using a match?

When one end of a capillary tube is dipped in water,the height of the water column is $h$. The upward force of $108 \ dyne$ due to surface tension is balanced by the force due to the weight of the water column. What is the inner circumference of the capillary (in $cm$)? (Surface tension of water $T = 7.2 \times 10^{-2} \ N/m$)

Water rises up to $10 \, cm$ height in a long capillary tube. If this tube is immersed in water so that the height above the water surface is only $8 \, cm$,then:

$A$ capillary tube of radius $r$ is initially just vertically completely immersed inside a liquid of angle of contact $0^{\circ}$. If the tube is slowly raised,then the relation between the radius of curvature of the meniscus inside the capillary tube and the displacement $(h)$ of the tube can be represented by:

Two narrow tubes of diameters $d_1$ and $d_2$ are joined together to form a $U$-tube open at both ends. If the $U$-tube contains water,the difference in water levels in the limbs is ($T$ is the surface tension of water,the angle of contact is zero,the density of water is $\rho$,and $g$ is the acceleration due to gravity).

Why is moisture retained in the soil when a farm is ploughed?