Fluid Mechanics MCQ Solved Paper for SBI PO

1. A flow is called sub-sonic, if the Mach number is
A. Less than unity
B. Unity
C. Between 1 and 6
D. More than 6
Answer : A

2. 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

3. The coefficient of discharge for an external mouthpiece is
A. 0.375
B. 0.5
C. 0.707
D. 0.855
Answer : D

4. A structure, whose width is __________ the width of the channel, is called a flumed structure.
A. Less than
B. More than
C. Equal
D. None of these
Answer : A

5. For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal
A. Ratio of inertial force to force due to viscosity
B. Ratio of inertial force to force due to gravitation
C. Ratio of inertial force to force due to surface tension
D. All the four ratios of inertial force to force due to viscosity, gravitation, surface tension, and elasticity
Answer : D

6. 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

7. When the Mach number is less than unity, the flow is called
A. Sub-sonic flow
B. Sonic flow
C. Super-sonic flow
D. Hyper-sonic flow
Answer : A

8. 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

9. In a free vortex motion, the radial component of velocity everywhere is
A. Maximum
B. Minimum
C. Zero
D. Nonzero and finite
Answer : C

10. Hydrometer is used to determine
A. Specific gravity of liquids
B. Specific gravity of solids
C. Specific gravity of gases
D. Relative humidity
Answer : A

11. Property of a fluid by which its own molecules are attracted is called
A. Adhesion
B. Cohesion
C. Viscosity
D. Compressibility
Answer : B

12. An error of 1% in measuring head over the apex of the notch (H) will produce an error of _________ in discharge over a triangular notch.
A. 1 %
B. 1.5 %
C. 2 %
D. 2.5 %
Answer : D

13. In a depressed 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 : B

14. A Piezometer tube is used only for measuring
A. Low pressure
B. High pressure
C. Moderate pressure
D. Vacuum pressure
Answer : C

15. Newton's law of viscosity is a relationship between
A. Shear stress and the rate of angular distortion
B. Shear stress and viscosity
C. Shear stress, velocity and viscosity
D. Pressure, velocity and viscosity
Answer : A

16. Steady 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 plane
Answer : B

17. For measuring flow by a Venturimeter, if should be installed in
A. Vertical line
B. Horizontal line
C. Inclined line with flow downward
D. In any direction and in any location
Answer : D

18. If 850 kg liquid occupies volume of one cubic meter, men 0.85 represents its
A. Specific weight
B. Specific mass
C. Specific gravity
D. Specific density
Answer : C

19. According to the principle of buoyancy a body totally or partially immersed in a fluid will be lifted up by a force equal to
A. The weight of the body
B. More than the weight of the body
C. Less than the weight of the body
D. Weight of the fluid displaced by the body
Answer : D

20. The sheet of water flowing over a notch or a weir is known as
A. Sill or crest
B. Nappe or vein
C. Orifice
D. None of these
Answer : B

21. The speed of sound in a ideal gas varies directly as its A. Absolute temperature
B. Temperature
C. Density
D. Modulus of elasticity
Answer : A

22. A manometer is used to measure
A. Low pressure
B. Moderate pressure
C. High pressure
D. Atmospheric pressure
Answer : C

23. The Francis formula for the discharge over Cipoletti weir is
A. 1.84 LH^1/2
B. 1.84 LH
C. 1.84 LH^3/2
D. 1.84 LH^5/2
Answer : C

24. According to Bazin's formula, the discharge over a rectangular weir is mL2g x H^3/2where m is equal to
A. 0.405 + (0.003/H)
B. 0.003 + (0.405/H)
C. 0.405 + (H/0.003)
D. 0.003 + (H/0.405)
Answer : A

25. A large Reynold number is indication of
A. Smooth and streamline flow
B. Laminar flow
C. Steady flow
D. Highly turbulent flow
Answer : D

26. Metacentric height is given as the distance between
A. The center of gravity of the body and the metacentre
B. The center of gravity of the body and the center of buoyancy
C. The center of gravity of the body and the center of pressure
D. Center of buoyancy and metacentre
Answer : A

27. 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

28. Liquids
A. Cannot be compressed
B. Occupy definite volume
C. Are not affected by change in pressure and temperature
D. None of the above
Answer : D

29. The conditions for the stable equilibrium of a floating body are
A. The metacentre should lie above the center of gravity
B. The center of buoyancy and the center of gravity must lie on the same vertical line
C. A righting couple should be formed
D. All the above are correct
Answer : D

30. Surface tension has the units of
A. Newton-sec/m
B. Newton-m/sec
C. Newton/m
D. Newton
Answer : C

31. One cubic metre of water weighs
A. 100 litres
B. 250 litres
C. 500 litres
D. 1000 litres
Answer : D

32. A vessel of 4 m³ contains oil which weighs 30 kN. The specific weight of the oil is
A. 4.5 kN/m³
B. 6 kN/m³
C. 7.5 kN/m³
D. 10 kN/m³
Answer : C

33. Stoke is the unit of
A. Kinematic viscosity in C. G. S. units
B. Kinematic viscosity in M. K. S. units
C. Dynamic viscosity in M. K. S. units
D. Dynamic viscosity in S. I. units
Answer : A

34. 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

35. The specific weight of sea water is __________ that of pure water.
A. Same as
B. Less than
C. More than
D. None of these
Answer : C

36. 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

37. Bernoulli's equation is applied to
A. Venturimeter
B. Orifice meter
C. Pitot tube
D. All of these
Answer : D

38. A perfect gas
A. Has constant viscosity
B. Has zero viscosity
C. Is in compressible
D. None of the above
Answer : D

39. The divergent portion of a Venturimeter is made longer than convergent portion in order to
A. Avoid the tendency of breaking away the stream of liquid
B. To minimise frictional losses
C. Both (A) and (B)
D. None of these
Answer : C

40. The bulk modulus of elasticity
A. Has the dimensions of 1/pressure
B. Increases with pressure
C. Is large when fluid is more compressible
D. Is independent of pressure and viscosity
Answer : B

41. 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

42. The force per unit length is the unit of
A. Surface tension
B. Compressibility
C. Capillarity
D. Viscosity
Answer : A

43. Flow of water in a pipe about 3 metres in diameter can be measured by
A. Orifice plate
B. Venturimeter
C. Rotameter
D. Pitot tube
Answer : D

44. The shear stress between the two liquid layers is __________ proportional to the distance between two layers.
A. Directly
B. Inversely
C. Both A and B
D. None of these
Answer : B

45. Total pressure on a lmxlm gate immersed vertically at a depth of 2 m below the free water surface will be
A. 1000 kg
B. 4000 kg
C. 2000 kg
D. 8000 kg
Answer : A

46. Which of the following is an example of laminar flow?
A. Underground flow
B. Flow past tiny bodies
C. Flow of oil in measuring instruments
D. All of these
Answer : D

47. The length of the divergent cone in a Venturimeter is __________ that of the convergent cone.
A. Equal to
B. Double
C. Three to four times
D. Five to six times
Answer : C

48. The rise of liquid along the walls of a revolving cylinder about the initial level is __________ the depression of the liquid at the axis of rotation.
A. Same as
B. Less than
C. More than
D. None of these
Answer : A

49. The ratio of absolute viscosity to mass density is known as
A. Specific viscosity
B. Viscosity index
C. Kinematic viscosity
D. Coefficient of viscosity
Answer : C

50. The pressure of a liquid measured with the help of a Piezometer tube is
A. Vacuum pressure
B. Gauge pressure
C. Absolute pressure
D. Atmospheric pressure
Answer : B