Q. No.A liquid does not wet the solid surface if the angle of contact is:
1. equal to \(45^{\circ}\)
2. equal to \(60^{\circ}\)
3. greater then \(90^{\circ}\)
4. zero
1. equal to \(45^{\circ}\)
2. equal to \(60^{\circ}\)
3. greater then \(90^{\circ}\)
4. zero
A metal block of area \(0.10~\text{m}^{2}\) is connected to a \(0.010~\text{kg}\) mass via a string that passes over an ideal pulley (considered massless and frictionless), as in the figure below. A liquid film with a thickness of \(0.30~\text{mm}\) is placed between the block and the table. When released the block moves to the right with a constant speed of \(0.085~\text{m/s}.\) The coefficient of viscosity of the liquid is:
1. \(4.45 \times 10^{-2}~\text{Pa-s}\)
2. \(4.45 \times 10^{-3}~\text{Pa-s}\)
3. \(3.45 \times 10^{-2}~\text{Pa-s}\)
4. \(3.45 \times 10^{-3}~\text{Pa-s}\)
Streamline flow is more likely for liquids with
| (a) | high density. | (b) | high viscosity. |
| (c) | low density. | (d) | low viscosity. |
Choose the correct option:
| 1. | (a), (b) | 2. | (c), (d) |
| 3. | (b), (c) | 4. | (a), (d) |
| (a) | gases decrease. | (b) | liquids increase. |
| (c) | gases increase. | (d) | liquids decrease. |
Which of the following options is/are correct?
| 1. | (b), (c) | 2. | (a), (d) |
| 3. | (c), (d) | 4. | (a), (b) |
The velocity of a small ball of mass \(M\) and density \(d\), when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is \(\dfrac{d}{2}\) then the viscous force acting on the ball will be:
1. \(\dfrac{3Mg}{2}\)
2. \(2Mg\)
3. \(\dfrac{Mg}{2}\)
4. \(Mg\)
The cylindrical tube of a spray pump has a cross-section of \(8.0\) cm2 one end of which has \(40\) fine holes each of diameter \(1.0\) mm. If the liquid flow inside the tube is \(1.5\) m-min–1, the speed of ejection of the liquid through the holes is:
1. \(0.64\) ms-1
2. \(0.74\) ms-1
3. \(0.54\) ms-1
4. \(0.84\) ms-1
A liquid can easily change its shape but a solid can not because:
| 1. | the density of a liquid is smaller than that of a solid. |
| 2. | the forces between the molecules is stronger in solid than in liquids. |
| 3. | the atoms combine to form bigger molecules in a solid. |
| 4. | the average separation between the molecules is larger in solids. |
In a horizontal pipe of a non-uniform cross-section, water flows with a velocity of \(1~\text{ms}^{-1}\) at a point where the diameter of the pipe is \(20 ~\text{cm}.\) The velocity of water \((\text{ms}^{-1})\) at a point where the diameter of the pipe is \(5~\text{cm}\) is:
1. \(8\)
2. \(16\)
3. \(24\)
4. \(32\)
Given below are two statements:
| Assertion (A): | Water flows through a smooth horizontal tube with a narrowing cross-section and its pressure increases. |
| Reason (R): | Bernoulli's equation for fluids states that \(P+\dfrac{1}{2}\rho v^2+\rho gh= \) constant along a streamline. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
A capillary tube of radius \(r\) is immersed in water and water rises in it to a height \(h.\) The mass of the water in the capillary is \(5\) g. Another capillary tube of radius \(2r\) is immersed in water. The mass of water that will rise in this tube is:
| 1. | \(5.0\) g | 2. | \(10.0\) g |
| 3. | \(20.0\) g | 4. | \(2.5\) g |
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