Question

Calculate the radius of a capillary to have a rise of 3 cm when dipped in a vessel containing water of surface tension 7.2 × 102 N m1. The density of water is 1000 kg m3, angle of contact is zero, and g = 10 m s2.

Answer 1

$$\begin{gathered} Heightoftheliquidincapillaryisgivenby: \\ h=\frac{2T}{\rho gr} \\ Tistension=7.2\times {10}^{-2} \\ \rho isdensityofwater=1000kg/m^3 \\ h=3cm=0.03m \\ ristheradius \\ r=\frac{2T}{\rho gh}=\frac{2\times 7.2\times {10}^{-2}}{1000\times 10\times 0.03} \\ r=0.048cm \end{gathered}$$