By a surface of a liquid we mean

1. a geometrical plane like x = 0

2. all molecules exposed to the atmosphere

3. a layer of thickness of the order of 10^–8 m

4. a layer of thickness of the order of 10^–4 m

An ice cube is suspended in vacuum in a gravity-free hall. As the ice melts it

1. will retain its cubical shape

2. will change its shape to spherical

3. will fall down on the floor of the hall

4. will fly up

When water droplets merge to form a bigger drop:

Air is pushed into a soap bubble of radius r to double its radius. If the surface tension of the soap solution is S, the work done in the process is

1. 8 \(\pi\) r² S

2. 12 \(\pi\) r² S

3. 16 \(\pi\) r² S

4. 24 \(\pi\) r² S

If more air is pushed in a soap bubble, the pressure in it

1. decreases

2. increases

3. remains same

4. becomes zero

If two soap bubbles of different radii are connected by a tube,

The figure shows a capillary tube of radius r dipped into water. If the atmospheric pressure is P₀, the pressure at point A is pressure at point A is

1. \(P_{0}\)

2. \(P_{0}+\frac{2 S}{r}\)

3. \(P_{0}-\frac{2 S}{r}\)

4. \(P_{0}-\frac{4 S}{r}\)

The excess pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is

1. 4

2. 2

3. 1

4. 0.125

Which of the following graphs may represent the relation between the capillary rise h and the radius r of the capillary?

1.

2.

3.

4.

Water rises in a vertical capillary tube upto a length of 10 cm. If the tube is inclined at 45°, the length of water risen in the tube will be

1. 10 cm

2. 10\(\sqrt2\)cm

3. 10/\(\sqrt2\)cm

4. none of these