Question

A tube of $1mm$ bore is dipped into a vessel containing a liquid of density $0.8g/{cm}^3$, surface tension $30dyne/cm$ and zero angle of contact. Calculate the length which the liquid will occupy in the tube when the tube is held

(a) vertical

(b) inclined to the vertical at an angle of ${30}^o$.

Answer 1

$P_A=\frac{2T}{r}\frac{2T}{r}=\rho ghh=\frac{2T}{\rho gr}$

$\left(a\right)$$h=\frac{2\times 30\times 2}{0.8\times 10\times 10}=\frac{3}{2}\times {10}^{-7}m$

$\left(b\right)$ Effective height$=h\sin 30h^{\prime }=\frac{3}{4}\times {10}^{-7}m$