Water is flowing in a streamline motion through a tube with its axis horizontal. Consider two points \(A\) and \(B\) in the tube at the same horizontal level.
| (a) | The pressures at \(A\) and \(B\) are equal for any shape of the tube. |
| (b) | The pressures are never equal. |
| (c) | The pressures are equal if the tube has a uniform cross-section. |
| (d) | The pressures may be equal even if the tube has a non–uniform cross-section. |
Choose the correct option from the given ones:
| 1. | (a) and (b) only |
| 2. | (b) and (c) only |
| 3. | (c) and (d) only |
| 4. | All of these |
There is a small hole near the bottom of an open tank filled with a liquid. The speed of the water ejected does not depend on:
| (a) | area of the hole |
| (b) | the density of the liquid |
| (c) | height of the liquid from the hole |
| (d) | acceleration due to gravity |
Choose the correct option from the given ones:
| 1. | (a) and (b) only |
| 2. | (b) and (c) only |
| 3. | (c) and (d) only |
| 4. | all of these |
By the 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 \(10^{-8}~\text m\) |
| 4. | a layer of thickness of the order of \(10^{-4}~\text m\) |
An ice cube is suspended in a 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:
| 1. | energy is liberated. |
| 2. | energy is absorbed. |
| 3. | energy is neither liberated nor absorbed. |
| 4. | energy may either be liberated or absorbed depending on the nature of the liquid. |
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,
| 1. | air flows from bigger bubble to the smaller bubble till the sizes become equal. |
| 2. | air flows from bigger bubble to the smaller bubble till the sizes are interchanged. |
| 3. | air flows from the smaller bubble to the bigger. |
| 4. | there is no flow of air. |
The figure shows a capillary tube of radius \(r\) dipped into water. If the atmospheric pressure is \(P_0,\) the pressure at point \(A\) is:

1. \(P_{0}\)
2. \(P_{0}+\dfrac{2 S}{r}\)
3. \(P_{0}-\dfrac{2 S}{r}\)
4. \(P_{0}-\dfrac{4 S}{r}\)
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