Question:
The angle of contact at the interface of water-glass is 0o, ethyl alcohol-glass is 0o, mercury-glass is 140o, and methyl iodide-glass is 30o. 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) water
(b) ethyl alcohol
(c) mercury
(d) methyl iodide
Solution:
The correct answer (c) mercury