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?

One end of a capillary tube is dipped in water,the rise of water column is $h$. The upward force of $98 \text{ dyne}$ due to surface tension is balanced by the force due to the weight of the water column. The inner circumference of the capillary is (surface tension of water $= 7 \times 10^{-2} \text{ Nm}^{-1}$) (in $\text{ cm}$)

In a capillary tube of radius $R$,a straight thin metal wire of radius $r$ $(R > r)$ is inserted symmetrically,and one end of the combination is dipped vertically in water such that the lower end of the combination is at the same level. The rise of water in the capillary tube is $[T =$ surface tension of water,$\rho =$ density of water,$g =$ gravitational acceleration$]$.

On putting a capillary tube in a pot filled with water,the level of water rises up to a height of $4 \,cm$ in the tube. If a tube of half the diameter is used instead,the water will rise to a height of nearly ............. $cm$.

The maximum length of a water column that can stay without falling in a vertically held capillary tube of diameter $1 \ mm$ and open at both ends is (Acceleration due to gravity $= 10 \ ms^{-2}$ and surface tension of water $= 0.07 \ Nm^{-1}$) (in $cm$)

If the liquid level falls in a capillary tube,then the radius of the capillary will: