chemical engineering fluid mechanics for chemical chemical engineering Mcqs
501. In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature) ?
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A. 1/?T

B. 1/T

C. T

D. ?T
502. Pick out the wrong statement pertaining to fluid flow ?
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A. The Newtonian fluid velocity in a circular pipe flow is maximum at the centre of the pipe

B. circular pipes is 0.5</strong>

C. The ratio of average velocity to the maximum velocity for turbulent flow of Newtonian fluid

D. Navier-Stokes equation is applicable to the analysis of viscous flows

E. Hagen-Poiseuille equation is applicable to the laminar flow of Newtonian fluids

503. Flow measurement in an open channel is done by a/an ________________?
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A. Venturimeter

B. Rotameter

C. Weir

D. Orificemeter

504. With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the____________________?
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A. Velocity increases

B. Pressure decreases

C. Both A. & B.

D. Neither A. nor B.

505. Cavitation in a centrifugal pump can be avoided by keeping the__________________?
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A. Inlet pressure low

B. Outlet pressure low

C. Inlet pressure high

D. Outlet pressure high

506. The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by (where, x = each side of the square duct) ?
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A. ?(x/2)

B. ?(2x)

C. ?(?x)

D. x
507. Boundary layer separation is caused by the_________________?
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A. Reduction of pressure gradient to zero

B. Boundary layer thickness reducing to zero

C. Adverse pressure gradient

D. Reduction of pressure to vapour pressure

508. The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its__________________?
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A. None of these

B. Specific volume

C. Viscosity

D. Velocity

509. Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid________________?
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A. Is independent of the specific weight of the fluid

B. Is different for different fluids

C. Lies above the centroid of the plane surface

D. Is at the centroid of the plane surface

510. Nominal size of the discharge pipe of a pump is usually _____________ the nominal size of the inlet pipe?
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A. Twice

B. Larger than

C. Smaller than

D. Same as

511. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the_________________?
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A. Discharge

B. Discharge minus vapor pressure of the liquid at the discharge temperature

C. Suction

D. Suction minus vapor pressure of the liquid at suction temperature
512. A gas (density = 1.5 kg/m3, viscosity = 2 10?5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 10?5kg/m.s flowing at 3 m/s will be________________?
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A. 16800 Pa/m

B. 18900 Pa/m

C. 8400 Pa/m

D. 12600 Pa/m
513. In the laminar boundary layer flow over a flat plate, the ratio (?/x) varies as: (where, ? is the boundary layer thickness and x is the distance from the leading edge in the direction of flow)?
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A. 1/Re

B. Re

C. Re-1/2

D. ?Re

514. Cocks are used to control ___________________?
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A. Solids

B. None of these

C. Water

D. Any liquid
515. Volute type of casing is provided in a centrifugal pump to___________________?
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A. Increase the discharge

B. Reduce the discharge fluctuation

C. Convert pressure head to velocity head

D. Convert velocity head to pressure head

516. Vena-contracta pressure tapping is at a distance _______________ from the position of an orificemeter fitted in a pipe of internal diameter d ?
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A. 0.5 d

B. 2d

C. d

D. 4d

517. The ratio of wall drag to total drag in the Stokes law range is_________________?
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A. 0.5

B. 1

C. 3-Jan

D. 2/3
518. A special type of liquid transporting device is the diffuser pump, in which _____________ are minimised?
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A. Disk friction

B. Cavitation

C. Shock losses

D. Bearing losses

519. Gradually varied flow in open channel is a/an ____________ flow?
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A. Steady uniform

B. Unsteady non-uniform

C. Unsteady uniform

D. Steady non-uniform
520. One horsepower is equal to________________?
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A. 550 lbf.ft/second

B. 550 kgf.m/second

C. Both A. and B.

D. 550 lbf.ft./hr

521. A fluid whose apparent viscosity increases with shear rate is termed as the _____________ fluid?
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A. Non-viscous

B. Dilatant

C. Newtonian

D. Viscous

522. A differential pressure cell is used for____________________________?
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A. Measuring small pressure difference in gases

B. Measuring small pressure difference in liquids

C. Remote recording of pressure difference

D. Measuring the difference of the impact & the static pressure

523. Cp/Cv is termed as__________________?
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A. Prandtl number

B. Mach number

C. Weber number

D. Adiabatic constant
524. For the manometer set up shown in the figure, the pressure difference PA PB is given by_________________?
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A. (?H ?L) gL + (?L ?air)gH

B. (?H ?L) gH + (?L ?air) . g(L H)

C. (?H ?air)gH

D. (?H ?L)gH

525. For one dimensional flow of an incompressible fluid in unsteady state in x-direction, the continuity equation is given by_______________?
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A. ?(?u)/?x = 0

B. (?u/?x) = (??/?t)

C. ?u/?x = 0

D. ??/?t = 0

526. The pressure head of a flow meter remains constant for_________________?
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A. Rotameter

B. Orificemeter

C. Venturimeter

D. Pitot tube

527. The maximum delivery pressure of compressors can be upto _____________ atmospheres?
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A. 10

B. 1000

C. 100

D. 250

528. For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe, plot is____________________?
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A. -1

B. -0.5

C. 1

D. 0.5

529. The terminal velocity of a solid spherical particle falling through a stationary fluid mass in the Stokes law range is proportional to the_____________________?
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A. Difference in the densities of the particle & fluid

B. Square of particle size

C. All A., B. and C.

D. Inverse of fluid viscosity

530. Turbulent flow generally occurs for cases involving__________________?
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A. None of these

B. Very narrow passages

C. Highly viscous fluid

D. Very slow motion

531. Drag force acting on a body does not depend upon the____________________?
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A. Density of the body

B. Density of the fluid

C. Velocity of the body

D. Projected area of the body

532. For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is _______________?
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A. More or less, depending on the type of particle

B. Equal

C. More

D. Less

533. A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation ?
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A. None of the above

B. Drag force and gravitational forces are important

C. Inertial and drag forces are important

D. Drag, gravitational and buoyancy forces are important
534. Steady flow occurs, when the__________________?
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A. Conditions do not change with time at any point

B. Rate of the velocity change is constant

C. Conditions are the same at the adjacent points at any instant

D. Conditions change steadily with time

535. The centre of pressure is_________________?
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A. At the centroid of the submerged area

B. A point on the line of action of the resultant force

C. Always below the centroid of the area

D. Always above the centroid of the area

536. Hydraulic intensifier is used for increasing the ___________________?
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A. Rate of flow through delivery pipeline of a pump

B. Intensity of pressure of the liquid

C. Momentum rate through delivery pipe

D. Rate of velocity of liquid supply

537. Fluid flow at increasing rate through a diverging pipe is an example of ______________ flow?
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A. Non-steady non-uniform

B. Non-steady uniform

C. Steady non-uniform

D. Steady uniform

538. Which of the following may be termed as a variable orifice flow-meter ?
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A. All A., B. and C.

B. Pitot tube

C. Rotameter

D. V-notch

539. The phenomenon occuring during pumping of a liquid solution containing dissolved gases, which may come out of the solution giving rise to gas pockets, is termed as_______________?
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A. Sublimation

B. Stripping

C. Cavitation

D. Evaporation

540. Interstage coolers are provided in a multistage compressor to____________________?
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A. Achieve the exact delivery pressure

B. Save power in compressing a given volume to a given pressure

C. Cool the delivered air

D. None of these

541. For flow of fluids through packed bed, the superficial velocity is_________________?
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A. Dependent on the pressure drop across the bed

B. Same as the average velocity through channels

C. More than the average velocity through channels

D. Less than the average velocity through channels
542. The pitot static tube does not measure the _____________ pressure?
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A. All A., B. and C.

B. Static

C. Difference in static & dynamic

D. Total

543. The pressure drop per unit length of pipe incurred by a fluid X flowing through pipe is ?p. If another fluid Y having both the specific gravity & density just double of that of fluid X, flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be__________________?
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A. 2?p

B. ?p2

C. ?p/2

D. ?p

544. In case of centrifugal fan or blower, the gas capacity varies as __________________?
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A. (Speed)2

B. Speed

C. (Speed)0.5

D. (Speed)3

545. The temperature in isentropic flow_______________?
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A. Cannot drop and then increase again downstream

B. Depends on Mach number only

C. None of these

D. Does not depend on Mach number

546. The time taken for gravity flow of a fixed volume of liquid (as in Redwood viscometer) is directly proportional to its __________________?
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A. Ratio of absolute viscosity to density

B. Absolute viscosity

C. Density

D. Reynolds number

547. The Prandtl Pitot tube measures the__________________?
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A. Pressure difference in pipe flow

B. Pressure at a point

C. Average flow velocity

D. Velocity at a point in the flow
548. Pipes having diameter 14 inches or more are designated by their_________________?
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A. Schedule number

B. Outside diameter

C. Inside diameter

D. None of these

549. The dimension of kinematic viscosity is_________________?
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A. ML-2T-2

B. L2T-1

C. ML-2T-1

D. None of these

550. Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump ?
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A. Increasing the impeller speed and the volute area

B. Mounting of two or more impellers in series on a single shaft

C. Increasing the number of vanes in the impeller

D. Either of A., B. or C.