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°

If two soap bubbles of different radii are in communication with each other

1. Air flows from larger bubble into the smaller one

2. The size of the bubbles remains the same

3. Air flows from the smaller bubble into the large one and the larger bubble grows at the expense of the smaller one

4. The air flows from the larger