We stated in Example 11.12 that a xylem tube is of radius $2.50\times 10^{-5}\text{ m}$. Verify that such a tube raises sap less than a meter by finding $h$ for it, making the same assumptions that sap's density is $1050{\text{ kg/m}}^3$ , its contact angle is zero, and its surface tension is the same as that of water at $20.0^{\circ }\text{C}$.

Video Transcript

This is College Physics Answers with Shaun Dychko. We're given this formula here for the height that a tube can pull up a liquid with capillary action, and the liquid is sap with a density of 1050 kilograms per cubic meter. The surface tension of the sap we're told is the same as that of water at 20 degrees Celsius so we put 0.0728 newtons per meter in place of gamma. We're told that the contact angle of the liquid is zero. We have 9.8 here for g and two and a half times ten to the minus five meters is the radius of this xylem tube. Capillary action will pull it up 0.565 meters and that is indeed, less than one meter.