chemical engineering Mcqs
6651. For ideally incompressible fluid, the Mach number will be __________________?
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A. 1.5

B. 5

C. 1

D. 0

6652. The equation f-0.5 = 4.07 loge (NRe ?f)-0.6 is called the ____________?
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A. Von-Karman equation

B. Colebrook formula

C. None of these

D. Fanning equation

6653. A Rotameter through which air at room temperature and atmospheric pressure is flowing gives a certain reading for a flow rate of 100 cc/sec. If helium (molecular weight 4) is used and Rotameter shows the same reading, the flow rate (cc/sec) is__________________?
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A. 42

B. 325

C. 269

D. 26

6654. Boundary layer separation occurs when the____________________?
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A. Velocity of sound is reached

B. Valve is closed in a pipeline

C. Cross-section of the channel is reduced

D. Pressure reaches a minimum

6655. Check in a centrifugal pump is________________?
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A. Provided in the discharge line

B. Generally a globe valve

C. Provided to prevent liquid from backing up through the pump when the pump is turned off or

D. All A., B. and C.

E. idently stops running

6656. The line of action of the buoyant force passes through the centre of gravity of the_______________________?
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A. Submerged body

B. Volume of fluid vertically above the body

C. Displaced volume of the fluid

D. Horizontal projection of the body

6657. The dimension of kinematic viscosity is_________________?
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A. ML-2T-2

B. ML-2T-1

C. None of these

D. L2T-1
6658. In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the _____________ efficiency?
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A. Volumetric

B. Mechanical

C. Overall

D. Manometric
6659. The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is_________________?
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A. 0.3

B. 0.9

C. 0.03

D. 0.66

6660. Very small pressure difference (< 5 mm water column) can be most conveniently measured by a/an _____________ manometer?
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A. Inclined tube mercury

B. U-tube water

C. U-tube mercury

D. Inclined tube water
6661. 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
6662. Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.) ?
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A. d2/3

B. d4/5

C. ?d

D. d1/3

6663. Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have_____________?
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A. High vibrations

B. Higher capital &maintenance cost

C. Very low speeds

D. Smaller discharge

6664. Specific speed of a centrifugal pump relates it with another pump having the___________________?
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A. Same speed

B. Geometrical similarity

C. Dynamic similarity

D. Same efficiency

6665. Draining of shallow pits or sump is done by a sump pump, which is a ______________ pump?
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A. Centrifugal

B. Single stage vertical

C. Diffuser

D. Plunger

6666. Small pressure differences in liquids is measured using a/an__________________?
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A. None of these

B. Pitot tube

C. U-tube manometer

D. Inclined tube manometer
6667. While starting a centrifugal pump, its delivery valve should be kept___________________?
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A. Closed

B. Opened

C. Either opened or closed; depending on the fluid viscosity

D. Either opened or closed; it does not make any difference

6668. What is the normal range of exit cone angle of a Venturimeter ?
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A. >25

B. 15 to 25

C. 7 to 15

D. 2 to 5

6669. The Stokes stream function applies to the________________?
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A. None of these

B. Ideal/non i viscous fluids only

C. Irrotational flow only

D. Cases of axial symmetry
6670. 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 ?air)gH

C. (?H ?L)gH

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

6671. For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter) ?
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A. D2

B. 1/D5

C. 1/D

D. 1/D2

6672. 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. ?p2

B. ?p/2

C. ?p

D. 2?p
6673. Friction produced by the formation of wakes is called the ______________ friction?
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A. None of these

B. Skin

C. Form

D. Disk

6674. 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 = 0

C. ??/?t = 0

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

6675. Baffles in mixing tanks are provided to__________________?
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A. Aid in rotational flow

B. None of these

C. Increase the structural strength of the tank

D. Reduce swirling and vortex formation
6676. Stokes law is valid, when NRe, p is less than_________________?
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A. 100

B. 700

C. 2

D. 2100

6677. For flow through a venturi at a particular discharge, the correct relationships among velocities at point X, Y and Z would be __________________?
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A. V2 > V1 and V2 > V3

B. V1 < V2 < V3

C. None of these

D. V1 > V2 > V3

6678. A fluid whose apparent viscosity increases with shear rate is termed as the _____________ fluid?
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A. Newtonian

B. Dilatant

C. Viscous

D. Non-viscous

6679. The head loss due to sudden expansion is__________________?
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A. (V12 V22)/gc

B. (V12 V22)/2gc

C. (V1 V2)2/2gc

D. (V1 V2)/2gc

6680. Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the___________________?
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A. Fluid velocity in the pipe

B. Time taken to close the valve

C. Pipe length

D. All A., B. and C.
6681. Cocks are used to control ___________________?
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A. Water

B. None of these

C. Solids

D. Any liquid
6682. Which of the following pipe bends will incur the largest head loss ?
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A. U-bend

B. 45 bend

C. 90 bend

D. 30 bend

6683. A lubricant 100 times more viscous than water would have a viscosity (in Pa.s) ?
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A. 1

B. 10

C. 0.01

D. 0.1
6684. A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be__________________?
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A. 200

B. 160

C. 100

D. 320

6685. A centrifugal pump loses prime after starting. The reason of this trouble may be_____________________?
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A. Too high a suction lift

B. All A., B., and C.

C. Low available NPSH and air leaks in the suction pipe

D. Incomplete priming

6686. Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of_________________?
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A. All A, B & C

B. Low melting point semi-solids

C. Liquids

D. Powder & granular solids

6687. The continuity equation in ideal fluid flow states that__________________?
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A. Energy is constant along a streamline

B. Energy is not constant along a streamline

C. Net rate of inflow into any small volume must be zero

D. There exists a velocity potential

6688. In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is_________________?
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A. 1.25

B. 1.84

C. 0.84

D. 0.5

6689. Two dimensional stream function________________?
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A. Relates velocity and pressure

B. Is constant along a stream line

C. None of these

D. Is constant along an equipotential surface

6690. For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter) ?
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A. Vs/Dp2

B. Vs2/Dp3

C. Vs2/Dp2

D. Vs/Dp3

6691. 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

6692. The pipe wall thickness is minimum for a pipe of given nominal size having schedule number___________________?
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A. 80

B. 40

C. 160

D. 120

6693. Isotropic turbulence occurs __________________?
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A. Where there is no velocity gradient

B. At higher temperatures

C. None of these

D. Only in Newtonian fluids

6694. The fluid property which matters for falling rain drops to acquire spherical shape is its__________________?
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A. Height of descend

B. Viscosity

C. Surface tension

D. Pressure

6695. The normal stress is the same in all directions at a point in a fluid, when the fluid is__________________?
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A. Non-viscous

B. Incompressible

C. Both A. and B.

D. Having no motion of one fluid layer relative to the other
6696. Net positive suction head (NPSH) of a centrifugal pump must be____________________?
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A. Greater than the vapour pressure of the liquid

B. Less than barometric pressure

C. Equal to the vapour pressure of the liquid

D. Less than the vapour pressure of the liquid

6697. Characteristic curves for a centrifugal pump plotted against its capacity is shown in the diagram. x, y and z denote respectively_______________?
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A. Efficiency, B.H.P. and head

B. Efficiency, head and B.H.P.

C. Head, efficiency and B.H.P.

D. B.H.P., efficiency and head

6698. The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is__________________?
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A. Parabolic

B. Flat

C. Parabolic near the wall and flat in the middle

D. Flat near the wall and parabolic in the middle

6699. Interstage coolers are provided in a multistage compressor to____________________?
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A. Save power in compressing a given volume to a given pressure

B. Achieve the exact delivery pressure

C. None of these

D. Cool the delivered air

6700. Each term of the Bernoullis equation written in the form, (p/?) + (g/gc). Z + (v2/2gc) = constant, represents the total energy per unit ________________?
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A. None of these

B. Specific weight

C. Mass

D. Volume