$A$ $U$-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:

When a capillary is dipped in water,water rises $0.015 \ m$ in it. If the surface tension of water is $75 \times 10^{-3} \ N/m$,the radius of the capillary is ....... $mm$.

$A$ uniform capillary tube of inner radius $r$ is dipped vertically into a beaker filled with water. The water rises to a height $h$ in the capillary tube above the water surface in the beaker. The surface tension of water is $\sigma$. The angle of contact between water and the wall of the capillary tube is $\theta$. Ignore the mass of water in the meniscus. Which of the following statements is (are) true?
$(A)$ For a given material of the capillary tube,$h$ decreases with increase in $r$.
$(B)$ For a given material of the capillary tube,$h$ is independent of $\sigma$.
$(C)$ If this experiment is performed in a lift going up with a constant acceleration,then $h$ decreases.
$(D)$ $h$ is proportional to contact angle $\theta$.

Fill in the blanks:
$(i)$ Smaller the radius of the capillary tube,...... the height of the column. ( more / less )
$(ii)$ If the meniscus is convex,then the liquid .......... in the capillary,and if it is concave,then the liquid .......... in the capillary. ( depressed / rises up )

The water rises in the capillary to a height of $10\, cm$. If the surface tension of water is $73 \times 10^{-3}\, N/m$,density is $10^3\, kg/m^3$ and $g = 9.8\, m/s^2$,then find the radius of the capillary. (in $, cm$)

During the capillary rise of a liquid in a capillary tube,the surface of contact that remains constant is of