Question

A capillary tube of radius 0.50 mm is dipped vertically in a pot of water. Find the difference between the pressure of the water in the tube 5.0 cm below the surface and atmospheric pressure. Surface tension of water is 0.075 $N{m}^{-}1$

• A. 160 pa
• B. 190 pa
• C. 200 pa
• D. 220 pa

Answer 1

Answer: (B)

190 pa

$\text{we know}$

excess pressure = $\rho gH$

$P=1000\times 9.8\times 5\times {10}^{-2}$

$=490N/m^2$

excess pressure in tube

$P_0=\frac{2T}{r}=\frac{2\times 0.75}{5\times {10}^{-4}}$

$P_0=300N/m^2$

$\Delta P=190N/m^2$

$Ans\omega er:-\left(B\right)$