Problem 2.168

When a vertical capillary of length \(l\) with the sealed upper end was brought in contact with the surface of a liquid, the level of this liquid rose to the height \(h\). The liquid density is \(\rho,\) the inside diameter of the capillary is \(d,\) the contact angle is \(\theta,\) the atmospheric pressure is \(p_{0} .\) Find the surface tension of the liquid.