question_answer

A ring is cut from a platinum tube 8.5 cm internal and 8.7 cm external diameter. It is supported horizontally from a pan of a balance so that it comes in contact with the water in a glass vessel. What is the surface tension of water if an extra 3.97 gm weight (in dyne/cm) is required to pull it away from water (\[g=980cm/{{\sec }^{2}}\]).

Answer:

72.13