Question

The surface tension of water at ${20}^{\circ }C$ is $75\times {10}^{-3}$ N/m. The difference in water surfaces within and outside an open-ended capillary tube of 1 mm internal bore, inserted at the water surface, would nearly be

• A. 7 mm
• B. 11 mm
• C. 15 mm
• D. 19 mm

Answer 1

The correct option is C 15 mm

In this problem, the bore is not defined properly. Here bore is used for radius.
$h=\frac{2\sigma cos\theta }{\rho .g.R}\frac{2(75\times {10}^{-3})}{{10}^3\times 9.81\times (1\times {10}^{-3})}=15.29mm$