Water from a pipe is coming at a rate of \(100\text{ liters per minute}.\) If the radius of the pipe is \(5\text{ cm},\) the Reynolds number for the flow is of the order of- (density of water = \(1000\text{ kg/m}^3,\) coefficient of viscosity of water = \(1 \text{ mPa-s}\))
1. \(10^4\)

2. \(10^3\)

3. \(10^2\)

4. \(10\)

Subtopic:  Viscosity |
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If \(M\) is the mass of water that rises in a capillary tube of radius \(r,\) then mass of water which will rise in a capillary tube of radius \(2r\) is:
1. \(M\)
2. \(4M\)
3. \(M/2\)
4. \(2M\)

Subtopic:  Capillary Rise |
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A wooden block is initially floating in a bucket of water with \(\dfrac{4}{5}\)​ of its volume submerged. When a certain amount of oil is poured into the bucket, the block is found to be just under the oil surface with half of its volume submerged in water and half in oil. What is the density of the oil relative to that of water?
1. \(0.7\)
2. \(0.5\)
3. \(0.8\)
4. \(0.6\)
Subtopic:  Archimedes' Principle |
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A hollow spherical shell of outer radius \(R\) floats just submerged beneath the surface of water. The inner radius of the shell is \(r.\) If the specific gravity of the shell material with respect to water is \(\dfrac{27}{8},\) what is the value of \(r\text{?}\)
\( \left (\text{use:}~19^{1/3}= \dfrac{8}{3}\right )\)

1. \(\dfrac{4}{9}R\) 2. \(\dfrac{8}{9}R\)
3. \(\dfrac{1}{3}R\) 4. \(\dfrac{2}{3}R\)
Subtopic:  Archimedes' Principle |
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In an adiabatic process, the density of a diatomic gas becomes \(32\) times its initial value. The final pressure of the gas is found to be \(n\) times the initial pressure. The value of \(n\) is:
1. \(326\)
2. \(\dfrac{1}{32}\)
3. \(32\)
4. \(128\)

Subtopic:  Types of Processes |
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In an experiment to verify Stokes's law, a small spherical ball of radius \(r\) and density \(\rho\) falls under gravity through a distance \(h\) in air before entering a tank of water. If the terminal velocity of the ball inside water is the same as its velocity just before entering the water surface, then the value of \(h\) is proportional to: (Ignore viscosity of air)
1. \(r\)
2. \(r^4\)
3. \(r^3\)
4. \(r^2\)

Subtopic:  Stokes' Law |
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A fluid is flowing through a horizontal pipe of varying cross-sections, with speed \(v\) ms-1 at a point where the pressure is \(P\) pascal. At another point where pressure is \(\dfrac{P}{2}\) pascal, its speed is \(V\) ms-1. If the density of the fluid is \(\rho\) kg-m-3 and the flow is streamlined, then \(V\) is equal to:

1. \(\sqrt{\dfrac{P}{2\rho }+v^{2}}\) 2. \(\sqrt{\dfrac{P}{\rho }+v^{2}} \)
3. \(\sqrt{\dfrac{2P}{\rho }+v^{2}}\) 4. \(\sqrt{\dfrac{P}{\rho }+v^{}}\)
Subtopic:  Bernoulli's Theorem |
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A reversible heat engine converts one-fourth of the heat input into work. When the temperature of the sink is reduced by \(52\) K, its efficiency is doubled. The temperature in of the source will be:
1. \(52\) K
2. \(104\) K
3. \(156\) K
4. \(208\) K

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The thermodynamic process is shown below on a P-V diagram for one mole of an ideal gas. If V2 = 2V1 then the ratio of temperature T2/T1 is :

1. 12

2. 2

3. 2

4. 12

Subtopic:  Types of Processes |
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\(1\) mole of rigid diatomic gas performs a work of \(\dfrac{Q}{5}\) when heat \(Q\) is supplied to it. Change in internal energy of the gas is:

1. \(\dfrac{4Q}{5}\) 2. \(\dfrac{3Q}{5}\)
3. \(\dfrac{Q}{5}\) 4. \(\dfrac{2Q}{5}\)
Subtopic:  First Law of Thermodynamics |
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