Fluid Mechanics

21.A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now

1. Increase
2. Decrease
3. Remain same
4. Data insufficient to predict

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22.A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a _________ pump.

1. Sump
2. Volute
3. Vacuum
4. Submerged

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23.A differential pressure cell is used for

1. Measuring small pressure difference in gases
2. Measuring small pressure difference in liquids
3. Remote recording of pressure difference
4. Measuring the difference of the impact & the static pressure

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24.A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double

1. Head
2. Discharge
3. Efficiency
4. None of these

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25.A floating/submerged body is always stable, if its centre of gravity

1. Lies above its centre of buoyancy
2. And centre of buoyancy coincide
3. Lies below its centre of buoyancy
4. Lies above its metacentre

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26.A fluid (μ/ρ) = 0.01 cm²/sec is moving at critical flow condition (N_Re = 2100) through a pipe of dia 3 cms. Velocity of flow is _________ cm/sec.

1. 7
2. 700
3. 7000
4. 630

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27.A fluid element has a velocity V = -y². xi + 2yx² . j. The motion at (x, y) = (1/√2, 1) is

1. Rotational and incompressible
2. Rotational and compressible
3. Irrotational and compressible
4. Irrotational and incompressible

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28.A fluid is a substance, that

1. Has to be kept in a closed container
2. Is almost incompressible
3. Has zero shear stress
4. Flows when even a small shear is applied to it

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29.A fluid is pumped at the rate of 10 lb/sec to a height of 55 ft. The horse power required is _________ hp.

1. 1
2. 20363
3. 5.5
4. 20090

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30.A fluid is the one, which

1. Cannot remain at rest under the action of shear force
2. Continuously expands till it fills any container
3. Is incompressible
4. Permanently resists distortion

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