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
Which of the following graphs may represent the relation between the capillary rise \(h\) and the radius \(r\) of the capillary?
1. \(d\)
2. \(b\)
3. \(c\)
4. \(a\)
Water rises in a vertical capillary tube up to a length of \(10~\text{cm}.\) If the tube is inclined at \(45^\circ,\) the length of water rising in the tube will be:
1. \(10~\text{cm}\)
2. \(10\sqrt{2}~\text{cm}\)
3. \(10/\sqrt{2}~\text{cm}\)
4. none of these
A \(20~\text{cm}\) long capillary tube is dipped in water. The water rises up to \(8~\text{cm}.\) If the entire arrangement is put in a freely falling elevator, the length of the water column in the capillary tube will be:
1. \(8~\text{cm}\)
2. \(6~\text{cm}\)
3. \(10~\text{cm}\)
4. \(20~\text{cm}\)
(A) | The material of the tube. |
(B) | The length of the tube. |
(C) | The outer radius of the tube. |
(D) | The inner radius of the tube. |
1. | (A) and (B) only |
2. | (A), (B) and (C) only |
3. | (A), (B) and (D) only |
4. | All of the above |
When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary.
a. | the surface tension of the liquid must be zero. |
b. | the contact angle must be \(90^\circ.\) |
c. | the surface tension may be zero. |
d. | the contact angle may be \(90^\circ.\) |
Choose the correct option:
1. | (a) and (b) |
2. | (b) and (c) |
3. | (c) and (d) |
4. | all of these |