Two small drops of mercury, each of radius r, coalesce to form a single large drop. The ratio of the total surface energies before and after the change is

1. $1:2^{1/3}$

2. $2^{1/3} :1$

3. 2:1

4. 1:2

If two soap bubbles of equal radii r coalesce then the radius of curvature of interface between two bubbles will be

(1) r                                 

(2) 0

(3) Infinity                         

(4) 1/2r

The angle of contact between glass and mercury is

(1) 0°

(2) 30°

(3) 90°

(4) 135°

A mercury drop does not spread on a glass plate because the angle of contact between glass and mercury is

(1) Acute

(2) Obtuse

(3) Zero

(4) $90°$

The liquid meniscus in the capillary tube will be convex if the angle of contact is

(1) Greater than 90°

(2) Less than 90°

(3) Equal to 90°

(4) Equal to 0°

The value of contact angle for kerosene with a solid surface.

(1) 0°

(2) 90°

(3) 45°

(4) 33° 

Nature of meniscus for liquid of $0^0$ angle of contact

(1) Plane

(2) Parabolic

(3) Semi-spherical

(4) Cylindrical

A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is 

(1) Flat

(2) Concave

(3) Convex

(4) Cylindrical

For which of the two pairs, the angle of contact is same

(1) Water and glass; glass and mercury

(2) Pure water and glass; glass and alcohol

(3) Silver and water; mercury and glass

(4) Silver and chromium; water and chromium

If the surface of a liquid is plane, then the angle of contact of the liquid with the walls of the container is -

(1) Acute angle

(2) Obtuse angle

(3) 90°

(4) 0°