chemical engineering fluid mechanics for chemical chemical engineering Mcqs
1. The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis. The centre of pressure of a rectangular surface (of width w) immersed vertically in a static mass of fluid is at a depth of (where, y = depth of the liquid) ?
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A. 3y/4

B. 1/(y/4)

C. 2y/3

D. 1/(y/3)

2. The speed of a sound wave in a gas is analogous to the speed of ______________________?
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A. Flow in an open channel

B. A disturbance travelling upstream in moving fluid

C. An elementary wave in an open channel

D. None of these

3. Pressure co-efficient is the ratio of pressure forces to __________________________ forces?
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A. Gravity

B. Viscous

C. Inertial

D. None of these

4. For laminar flow of Newtonian fluid in a circular pipe, the velocity distribution is a function of the distance d measured from the centre line of the pipe, and it follows a ______________ relationship?
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A. Linear

B. Hyperbolic

C. Parabolic

D. Logarithmic

5. What is the value of Fanning friction factor f for smooth pipe at NRe = 106 approximately ?
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A. 0.1

B. 0.01

C. 0.3

D. 0.003
6. What is the maximum theoretical suction lift (metres) of a reciprocating pump ?
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A. 5

B. 100

C. 10

D. 50

7. Drag is defined as the force exerted by the___________________?
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A. None of these

B. Fluid on the solid in the direction of flow

C. Fluid on the solid in a direction opposite to flow

D. Solid on the fluid

8. Which of the following is used for very accurate measurement of flow of gas at low velocity ?
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A. Pitot tube

B. Segmental orificemeter

C. Hot wire anemometer

D. Rotameter

9. A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by________________?
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A. Decreasing the size of the inlet pipe

B. Increasing the size of the inlet pipe

C. Lowering the pump position

D. Both B. and C.
10. Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around________________?
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A. 10

B. 1000

C. 2000

D. 100

11. Stokes law is valid, when the particle Reynolds number is ______________________?
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A. < 1

B. < 5

C. > 1

D. None of these

12. At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump ?
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A. 20 and 120

B. 45 and 60

C. 40 and 140

D. 90 and 80

13. One poise (unit of absolute/dynamic viscosity) is equivalent to one_____________________?
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A. gm/cm. sec

B. gm/cm2. sec

C. cm2/sec

D. m2/sec

14. As per Newtons law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to (where, ? = fluid viscosity) ?
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A. 1/?

B. 1/?2

C. ?

D. ?2

15. Which of the following equations is valid for laminar flow of a fluid through packed bed ?
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A. Kozeny Karman equation

B. Blake-Plummer equation

C. Fanning equation

D. Hagen-Poiseuille equation

16. The blades of a centrifugal impeller are said to be curved forward, if the ____________ of the motion of impeller blades?
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A. Outlet tip of a blade curves in a direction opposite to that

B. Inlet tip of a blade curves in a direction opposite to that

C. Outlet tip of a blade is towards the direction

D. Inlet tip of a blade is towards the direction

17. In isotropic turbulence, the _____________ are equal to each other?
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A. None of these

B. Root mean square of velocity fluctuations in the three co-ordinate directions

C. Temporal velocity components

D. Mean square of velocity fluctuations in the three co-ordinate directions
18. Plunger pumps are used for__________________?
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A. None of these

B. Higher pressure

C. Slurries

D. Viscous mass

19. With increase in molecular weight of the gas, the head developed by a centrifugal compressor will________________?
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A. Increase

B. Remain same

C. Decrease

D. Unpredictable

20. Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newtons law of viscosity. (II) Newtons second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary?
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A. I, II, III

B. II, III, V

C. I, II, V

D. II, IV, V

21. Choose the set of pressure intensities that are equivalent ?
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A. 10 psi, 19.7 ft. of water, 5.3 inches of Hg

B. 10 psi, 19.7 ft. of water, 23.3 inches of Hg

C. 4.33 psi, 10 ft. of water, 20.7 inches of Hg

D. 4.33 psi, 10 ft. of water, 8.83 inches of Hg
22. Which of the following can be used to create a flow of gas, where no significant compression is required ?
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A. Reciprocating compressor

B. Blower

C. Centrifugal compressor

D. Axial flow compressor

23. Which is the most efficient and best for measuring very small flow rate of gases ?
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A. Orificemeter

B. Rotameter

C. Venturimeter

D. Flow nozzle

24. In laminar flow through a round tube, the discharge varies ______________________?
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A. As the square of the radius

B. Linearly as the viscosity

C. Inversely as the viscosity

D. Inversely as the pressure drop

25. When the water is warm, the height to which it can be lifted by a pump_________________?
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A. Increases due to increased vapour pressure

B. Decreases due to reduced viscosity

C. Decreases due to increased frictional resistance

D. Decreases due to reduced vapour pressure
26. The velocity for subsonic flow in a pipeline_______________?
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A. Decreases in the downstream direction

B. Increases in the downstream direction

C. Is independent of the area of flow

D. Is constant

27. The head loss due to sudden contraction is proportional to___________________?
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A. Velocity head

B. Velocity

C. None of these

D. Turbulence

28. Which of the following facilitates close control of flow of fluids ?
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A. Gate valve

B. Check valve

C. Globe valve

D. Butterfly valve

29. Pick out the correct statement pertaining to transition/ entrance length in fluid flow ?
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A. al to 50 D

B. All A., B. and C.

C. 5. D.NRe

D. The length of entrance region of pipe, in which full development of fluid flow takes place

E. h that velocity profile does not change downstream, is called the transition length

F. Transition length for turbulent flow of Newtonian fluids in a smooth pipe of diameter d is

30. The boundary layer is that part of a moving fluid, in which the fluid velocity is_________________?
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A. Constant

B. Affected by the presence of a solid boundary

C. All A., B. and C.

D. Affected by the fluid flow pressure

31. The pressure co-efficient is the ratio of pressure forces to ______________ forces?
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A. Gravity

B. Surface tension

C. Viscous

D. Inertial

32. A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit E. to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062 ?
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A. 10 m

B. 30 m

C. 11 m

D. 11.8 m

33. In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes_______________?
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A. More than liquid vapor pressure

B. More than atmospheric pressure

C. Less than atmospheric pressure

D. Less than liquid vapor pressure
34. In which of the following body shapes, the pressure drag is large compared to the friction drag ?
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A. Stream line body

B. None of these

C. Two dimensional body

D. Bluff body
35. In a dry packed bed, the pressure drop will be changed by increasing the flow rate as__________________?
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A. V

B. V-0.8

C. V-1

D. V1.8
36. Pascal law is not applicable for a/an ________________________ fluid?
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A. Uniformly moving

B. Static

C. None of these

D. Accelerating frictionless

37. Which of the following is a Newtonian fluid ?
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A. Sewage sludge

B. Rubber latex

C. Non-colloidal solution

D. Quicksand

38. Applicability of Bernoullis equation is limited to a/an _____________ fluid, that does not exchange shaft work with the surroundings?
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A. Incompressible

B. Non-viscous

C. Both A. and B.

D. Neither A. nor B.

39. The maximum delivery pressure of a reciprocating compressor may be about ______________ kg/cm2?
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A. 1000

B. 3000

C. 4000

D. 2000

40. Centrifugal pumps as compared to reciprocating pumps__________________?
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A. Run at a lower speed for the same discharge

B. Deliver fluid with pulsating/fluctuating discharge

C. Can be run with discharge line valve closed for a short interval

D. Do not need priming

41. Existence of boundary layer in fluid flow is because of the_________________?
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A. Fluid viscosity

B. Fluid density

C. Surface tension

D. Gravity forces

42. Air vessel fitted to a reciprocating pump____________________?
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A. Decreases the work done

B. Results in non-uniform discharge

C. Increases the work done

D. Causes cavitation

43. Identification of pipelines carrying different liquids and gases is done by the ____________ of the pipe?
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A. Altitude

B. Diameter

C. Colour

D. None of these

44. Drag force on the float of a Rotameter is (where Q = flow rate of the)__________________?
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A. Constant

B. ? ?Q

C. ? Q2

D. ? Q

45. Air vessel of a reciprocating pump is initially filled with___________________?
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A. Compressed air

B. None of these

C. Water

D. Atmospheric air

46. _____________ pump is the most suitable device for discharging a liquid against a pressure of ? 1500 kgf/cm2?
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A. Vane

B. Piston

C. Plunger

D. Centrifugal

47. For turbulent flow of Newtonian fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is ________________?
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A. 0.66

B. 0.5

C. 1

D. < 0.5

48. Which law/principle of solid mechanics is similar/equivalent to Newtons law of viscosity in fluid mechanics ?
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A. Archimedes principle

B. Hookes law

C. Newtons second law of motion

D. Newtons third law of motion

49. Self-priming centrifugal pump can be used for________________?
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A. All A., B. and C.

B. Pumping industrial wastes

C. Pumping liquid fertilisers (e.g. liquid NH3)

D. Booster service

50. Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?
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A. f1 = f2

B. f1 > f2

C. Data not sufficient to relate f1 & f2

D. f1 < f2