Question
Question: The angle of contact at the interface of water-glass is 0°, Ethylalcohol-glass is 0°, mercury-glass ...
The angle of contact at the interface of water-glass is 0°, Ethylalcohol-glass is 0°, mercury-glass is 140° and Methyliodide-glass is 30°. A glass capillary is put in a trough containing one of these four liquids. It is observed that the meniscus is convex. The liquid in the trough is
A
(a) Water
A
(b) Ethylalcohol
A
(c) Mercury
A
(d) Methyliodide
Explanation
Solution
(c) The meniscus of liquid in a capillary tube will be convex upwards if angle of contract is obtuse. It is so when one end of glass capillary tube is immersed in a trough of mercury.