Pure water rises through a height h in a capillary tube of internal radius r . Surface tension of water is T . The pressure difference between the water level in the container and the lowest point of the concave meniscus is

Step-by-step solution

The pressure difference responsible for capillary rise arises from Laplace's law governing curved liquid surfaces, where the excess pressure across a spherical meniscus is given by P = 2T R , with T representing surface tension and R the radius of curvature. For pure water and glass, the contact angle is approximately 0^ , making the meniscus hemispherical such that its radius of curvature equals the capillary's internal radius: R = r . This implies the pressure difference between the water level in the container (