If a capillary tube is immersed at first in cold water and then in hot water, the height of capillary rise will be smaller in the second case. How can this be explained?

Explanation

We know that h = `(2Scostheta)/(rrhog)`
Surface tension of hot water is less than the surface tension of cold water. Moreover, due to thermal expansion the radius of the capillary tube will increase in hot water. Due to both reasons, the height of capillary rise will be less in hot water as compared to cold water.