Question

The angle of contact at the interface of water-glass is $0^{\circ }$, Ethylalcohol-glass is $0^{\circ }$, mercury-glass is $140^{\circ }$ and Methyliodide-glass is $30^{\circ }$. 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. ethylalcohol
• C. mercury
• D. methyliodide

Answer 1

Answer: (C)

The meniscus of liquid in a capillary tube will be convex upwards if angle of contact is obtuse. It is so when one end of glass capillary tube is immersed in a trough of mercury