Fluid Mechanics MCQ Solved Paper for SBI Clerk

1. The discharge over a rectangular weir, considering the velocity of approach, is (whereH1 = H + Ha = Total height of water above the weir, H = Height of water over the crest of the weir, and Ha = Height of water due to velocity of approach)
A. (2/3) Cd × L.?2g [H1 - Ha]
B. (2/3) Cd × L. ?2g [H1 ^3/2 - Ha ^3/2]
C. (2/3) Cd × L.?2g [H1 ² - Ha ²]
D. (2/3) Cd × L. ?2g [H1 ^5/2 - Ha ^5/2]
Answer : B

2. Resultant pressure of the liquid in the case of an immersed body acts through
A. Centre of gravity
B. Centre of pressure
C. Metacentre
D. Centre of buoyancy
Answer : B

3. Which of the following is dimensionless?
A. Specific weight
B. Specific volume
C. Specific speed
D. Specific gravity
Answer : D

4. The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a rectangular notch is given by
A. dQ/Q = (1/2) × (dH/H)
B. dQ/Q = (3/4) × (dH/H)
C. dQ/Q = (dH/H)
D. dQ/Q = (3/2) × (dH/H)
Answer : D

5. Reynold's number is the ratio of the inertia force to the
A. Surface tension force
B. Viscous force
C. Gravity force
D. Elastic force
Answer : B

6. A water tank contains 1.3 m deep water. The pressure exerted by the water per metre length of the tank is
A. 2.89 kN
B. 8.29 kN
C. 9.28 kN
D. 28.9 kN
Answer : B

7. A flow whose streamline is represented by a curve, is called
A. One-dimensional flow
B. Two-dimensional flow
C. Three-dimensional flow
D. Four-dimensional flow
Answer : B

8. The flow in a pipe is turbulent when Reynold number is
A. Less than 2000
B. Between 2000 and 2800
C. More than 2800
D. None of these
Answer : C

9. The kinematic viscosity of an oil (in stokes) whose specific gravity is 0.95 and viscosity 0.011 poise, is
A. 0.0116 stoke
B. 0.116 stoke
C. 0.0611 stoke
D. 0.611 stoke
Answer : A

10. A fluid having no viscosity is known as
A. Real fluid
B. Ideal fluid
C. Newtonian fluid
D. Non-Newtonian fluid
Answer : B

11. When the pressure intensity at a point is more than the local atmospheric pressure, then the difference of these two pressures is called
A. Gauge pressure
B. Absolute pressure
C. Positive gauge pressure
D. Vacuum pressure
Answer : C

12. The difference of pressure between the inside and outside of a liquid drop is
A. p = T × r
B. p = T/r
C. p = T/2r
D. p = 2T/r
Answer : D

13. With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will
A. Decrease
B. Increase
C. Remain unchanged
D. Depend upon the characteristics of liquid
Answer : A

14. An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called
A. Weir
B. Notch
C. Orifice
D. None of these
Answer : B

15. Practical fluids
A. Are viscous
B. Possess surface tension
C. Are compressible
D. Possess all the above properties
Answer : D

16. For a floating body to be in stable equilibrium, its metacentre should be
A. Below the center of gravity
B. Below the center of buoyancy
C. Above the center of buoyancy
D. Above the center of gravity
Answer : D

17. The force present in a moving liquid is
A. Inertia force
B. Viscous force
C. Gravity force
D. All of these
Answer : D

18. In the case of steady flow of a fluid, the acceleration of any fluid particle is
A. Constant
B. Variable
C. Zero
D. Zero under limiting conditions
Answer : C

19. In a free nappe,
A. The pressure below the nappe is atmospheric
B. The pressure below the nappe is negative
C. The pressure above the nappe is atmospheric
D. The pressure above the nappe is negative
Answer : A

20. According to Francis formula, the discharge over a rectangular weir is (where n = Number of end contractions)
A. (2/3) × C_d (L - nH) × ?(2gh)
B. (2/3) × C_d (L - 0.1nH) × ?(2g) × H^3/2
C. (2/3) × C_d (L - nH) × ?(2g) × H²
D. (2/3) × C_d (L - nH) × ?(2g) × H^5/2
Answer : B

21. The surface tension of mercury at normal temperature is __________ that of water.
A. Same as
B. Lower than
C. Higher than
D. None of these
Answer : C

22. A one dimensional flow is one which
A. Is uniform flow
B. Is steady uniform flow
C. Takes place in straight lines
D. Involves zero transverse component of flow
Answer : D

23. The coefficient of discharge in case of internal mouthpiece is __________ that of external mouthpiece.
A. Less than
B. More than
C. Equal to
D. None of these
Answer : A

24. A flow in which the volume of a fluid and its density does not change during the flow is called _________ flow.
A. Incompressible
B. Compressible
C. Viscous
D. None of these
Answer : A

25. Cavitation is caused by
A. High velocity
B. High pressure
C. Weak material
D. Low pressure
Answer : D

26. Fluid is a substance which offers no resistance to change of
A. Pressure
B. Flow
C. Shape
D. Volume
Answer : C

27. The centre of gravity of the volume of the liquid displaced is called
A. Centre of pressure
B. Centre of buoyancy
C. Metacentre
D. None of these
Answer : B

28. Which of the following statement is correct?
A. In a compressible flow, the volume of the flowing liquid changes during the flow
B. A flow, in which the volume of the flowing liquid does not change, is called incompressible flow
C. When the particles rotate about their own axes while flowing, the flow is said to be rotational flow
D. All of the above
Answer : D

29. Non uniform flow occurs when
A. The direction and magnitude of the velocity at all points are identical
B. The velocity of successive fluid particles, at any point, is the same at successive periods of time
C. Velocity, depth, pressure, etc. change from point to point in the fluid flow.
D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Answer : C

30. The coefficient of discharge for an external mouthpiece depends upon
A. Velocity of liquid
B. Pressure of liquid
C. Area of mouthpiece
D. Length of mouthpiece
Answer : D

31. The most efficient section of a channel is
A. Triangular
B. Rectangular
C. Square
D. Trapezoidal
Answer : D

32. A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. Which of the following statement is correct?
A. The pressure on the wall at the liquid level is minimum
B. The pressure on the bottom of the wall is maximum
C. The pressure on the wall at the liquid level is zero, and on the bottom of the wall is maximum
D. The pressure on the bottom of the wall is zer
Answer : C

33. The Metacentric heights of two floating bodies A and B are 1 m and 1.5 m respectively. Select the correct statement.
A. The bodies A and B have equal stability
B. The body A is more stable than body B
C. The body B is more stable than body A
D. The bodies A and B are unstable
Answer : C

34. At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be
A. Minimum
B. Maximum
C. Zero
D. Could be any value
Answer : D

35. The shear stress-strain graph for a Newtonian fluid is a
A. Straight line
B. Parabolic curve
C. Hyperbolic curve
D. Elliptical
Answer : A

36. Uniform flow occurs when
A. The direction and magnitude of the velocity at all points are identical
B. The velocity of successive fluid particles, at any point, is the same at successive periods of time
C. The magnitude and direction of the velocity do not change from point to point in the fluid
D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each pleasure
Answer : C

37. A flow through a long pipe at decreasing rate is called __________ uniform flow.
A. Steady
B. Unsteady
C. Both A and B
D. None of these
Answer : B

38. Dimensions of surface tension are
A. ML°T?²
B. ML°T
C. ML r²
D. ML²T²
Answer : A

39. A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury?
A. 0.5
B. 0.4
C. 0.515
D. 0.5
Answer : C

40. The discharge over a right angled notch is (where H = Height of liquid above the apex of notch)
A. (8/15) C_d. 2g. H
B. (8/15) C_d. 2g. H^3/2
C. (8/15) C_d. 2g. H²
D. (8/15) C_d. 2g. H^5/2
Answer : D

41. The celerity (velocity) of a pressure wave in a fluid is given by (where K = Bulk modulus, and ? = Density of the fluid)
A. K.?
B. K/?
C. ?/K
D. None of these
Answer : B

42. The factional resistance of a pipe varies approximately with __________ of the liquid.
A. Pressure
B. Velocity
C. Square of velocity
D. Cube of velocity
Answer : C

43. The length AB of a pipe ABC in which the liquid is flowing has diameter (d1) and is suddenly enlarged to diameter (d2) at B which is constant for the length BC. The loss of head due to sudden enlargement is
A. (v? - v?)²/g
B. (v?² - v?²)/g
C. (v? - v?)²/2g
D. (v?² - v?²)/2g
Answer : C

44. The pressure at a point in a fluid will not be same in all the directions when the fluid is
A. Moving
B. Viscous
C. Viscous and static
D. Viscous and moving
Answer : D

45. The critical depth meter is used to measure
A. Velocity of flow in an open channel
B. Depth of flow in an open channel
C. Hydraulic jump
D. Depth of channel
Answer : C

46. The top of the weir over which the water flows is known as
A. Sill or crest
B. Nappe or vein
C. Orifice
D. None of these
Answer : A

47. A uniform body 3 m long, 2 m wide and 1 m deep floats in water. If the depth of immersion is 0.6 m, then the weight of the body is
A. 3.53 kN
B. 33.3 kN
C. 35.3 kN
D. None of these
Answer : C

48. According to Bernoulli's equation for steady ideal fluid flow
A. Principle of conservation of mass holds
B. Velocity and pressure are inversely proportional
C. Total energy is constant throughout
D. The energy is constant along a streamline but may vary across streamlines
Answer : D

49. Choose the wrong statement
A. The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface
B. The horizontal component acts through the center of pressure for the vertical projection
C. The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
D. The vertical component passes through the center of pressure of the volume
Answer : D

50. A streamline is defined as the line
A. Parallel to central axis flow
B. Parallel to outer surface of pipe
C. Of equal velocity in a flow
D. Along which the pressure drop is uniform
Answer : C