# Is Pascal's law incorrect?

Consider the figure given below.

Here I'm gonna talk about capillarity. The liquid inside the beaker as well as the column is water. As water has a tendency to rise in the capillary as shown, doesn't it violate Pascal's law.

At equilibrium when water has risen in the tube, pressure at point A as well as the pressure at water surface which is open to atmosphere will be $1$ $atm$. In turn pressure at point B will be $1$ $atm$ as it is at the same level above the ground as water in beaker ( Pascal's law ). Which means that $P_a-P_b$ is zero but according to Pascal's law it should have been $h\rho g$.

What's wrong then.

• Pressure at Point A(just inside liquid) is less than a point just above it. The discontinuity is due to the phenomenon of surface tension due to which the pressure across the meniscus is different.(Pressure suffers discontinuity at the meniscus) – Prasanna Aug 26 '18 at 16:27
• Again, asking "Is this well-established law incorrect?" appeals to me as a drastically bad question. It's much more reasonable to ask how a certain law can be applied to the given situation. Can you edit the title? – user191954 Sep 2 '18 at 6:10

As stated in the comments, the pressure at B is (approximately) equal to atmospheric pressure, so Pascal's law holds. The pressure in the tube above B is lower than atmospheric ($p_a=p_b-\rho gh$). The difference in pressure between the liquid and the atmosphere at A is compensated by the force of surface tension at the meniscus.