Fluid Mechanics

271.In an incompressible flow of fluid, the fluid

1. Temperature remains constant
2. Compressibility is greater than zero
3. Density does not change with pressure & temperature
4. Is frictionless

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272.In an incompressible fluid, the density is

1. Greatly affected by moderate changes in pressure
2. Greatly affected only by moderate changes in temperature
3. Not affected with moderate change in temperature & pressure
4. Sensible to changes in both temperature & pressure

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273.In area meter (e.g., Rotameter), with increase in the fluid flow rate, the

1. Pressure drop increases linearly
2. Pressure drop is almost constant
3. Area through which fluid flows does not vary
4. None of these

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274.In case of a _________ the energy of flow is considerably decreased downstream of the machine.

1. Blower
2. Turbine
3. Centrifugal pump
4. Centrifugal fan

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275.In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the _________ efficiency.

1. Manometric
2. Mechanical
3. Volumetric
4. Overall

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276.In case of a centrifugal pump, the theoretical head developed is dependent on the _________ the impeller.

1. Speed of
2. Diameter of
3. Fluid velocity leaving
4. All (A), (B) and (C)

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277.In case of a pipe exit fitted with a nozzle, the

1. Conversion of kinetic head to pressure head is facilitated
2. Conversion of pressure head to kinetic head is facilitated
3. Power transmitted through the nozzle is maximum, when the head lost due to friction in the pipe is equal to one third of the total supply head
4. Both (B) and (C)

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278.In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is

1. The velocity of sound
2. Dependent on its cross-sectional area
3. Dependent on fluid viscosity
4. Dependent on fluid density

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279.In case of a Rotameter, the density of the float material is _________ that of the liquid it replaces.

1. More than
2. Less than
3. Equal to
4. Either (A) or (B)

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280.In case of centrifugal fan or blower, the gas capacity varies as

1. Speed
2. (Speed)²
3. (Speed)³
4. (Speed)^0.5

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