It is not possible to write directly on blotting paper or newspaper with an ink pen.

Water rises to a height of $10 \,cm$ in a capillary tube. In which of the following conditions will it rise to a height much greater than $10 \,cm$ in a very long capillary tube?

$A$ $U$-tube is such that the diameter of one limb is $0.4\,mm$ and that of the other is $d\,mm$. If the surface tension of water contained in the tube is $0.07\,N/m$ and the difference in the levels of liquid in the limbs is $3.6\,cm$,then the value of $d$ is:

$A$ capillary tube of radius $r$ is immersed in water and water rises in it to a height $h$. The mass of the water in the capillary is $5 \, g$. Another capillary tube of radius $2r$ is immersed in water. The mass of water that will rise in this tube is $........ \, g$.

If the diameter of a capillary tube is doubled,then the height of the liquid that will rise is

Water rises in a capillary tube to a height of $3\, cm$ when one end is dipped vertically in it. If the surface tension of water is $75 \times 10^{-3}\, N/m$,then the diameter of the capillary tube will be....... $mm$. (Assume $g = 10\, m/s^2$)