Question

Match List I with List - II

List - I	List - II
a) Meniscus of water in a glass Capillary tube	e) convex
b) Meniscus of water in silver capillary tube	f) do not over flow
c) Meniscus of mercury in glass capillary tube	g) flat
d) Water in glass capillary tube of insufficient length	h) concave

The correct match is :

• A. a -- h; b-- g; c-- e; d-- f
• B. a -- e; b-- f;c-- g; d -- h
• C. a -- f; b-- e; c--g; d-- h
• D. a-- h; b-- g; c-- f; d-- e

Answer 1

Answer: (A)

a -- h; b-- g; c-- e; d-- f

In a mercury meniscus, the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass. Hence the meniscus is convex.

Opposite is the case in water meniscus, and hence concave meniscus is formed.

However in water in silver capillary tube, the two forces are equal and hence a flat meniscus is formed.

When length of capillary tube is insufficient of water, the water increases the angle of contact to increase the pressure inside the tube, balancing the excess pressure, and hence prevents the overflow.