Fluid Mechanics MCQ Solved Paper for SSC MTS

1. Falling drops of water become spheres due to the property of
A. Surface tension of water
B. Compressibility of water
C. Capillarity of water
D. Viscosity of water
Answer : A

2. During the opening of a valve in a pipe line, the flow is
A. Steady
B. Unsteady
C. Uniform
D. Laminar
Answer : B

3. The force of buoyancy is always __________ the weight of the liquid displaced by the body.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : A

4. The total head of a liquid particle in motion is equal to
A. Pressure head + kinetic head + potential head
B. Pressure head - (kinetic head + potential head)
C. Potential head - (pressure head + kinetic head)
D. Kinetic head - (pressure head + potential head)
Answer : A

5. A hemispherical tank of radius (R) has an orifice of cross-sectional area (a) at its bottom and is full of liquid. The time required to empty the tank completely is
A. 14? R^1/2/15C_d × a ?(2g)
B. 14? R^3/2/15C_d × a ?(2g)
C. 14? R^5/2/15C_d × a ?(2g)
D. 14? R^7/2/15C_d × a ?(2g)
Answer : C

6. The hammer blow in pipes occurs when
A. There is excessive leakage in the pipe
B. The pipe bursts under high pressure of fluid
C. The flow of fluid through the pipe is suddenly brought to rest by closing of the valve
D. The flow of fluid through the pipe is gradually brought to rest by closing of the valve
Answer : C

7. 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

8. 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

9. The normal stress in a fluid will be constant in all directions at a point only if
A. It is incompressible
B. It has uniform viscosity
C. It has zero viscosity
D. It is at rest
Answer : D

10. A weir is said to be broad crested weir, if the width of the crest of the weir is ________ half the height of water above the weir crest.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : C

11. When a body is immersed wholly or partially in a liquid, it is lifted up by a force equal to the weight of liquid displaced by the body. This statement is called
A. Pascal's law
B. Archimedess principle
C. Principle of floatation
D. Bernoulli's theorem
Answer : B

12. A venturi-flume is used to measure
A. Pressure of liquid
B. Discharge of liquid
C. Pressure difference between two points in a channel
D. Pressure difference between two points in a pipe
Answer : B

13. The discharge through a channel of rectangular section will be maximum, if
A. Its depth is twice the breadth
B. Its breadth is twice the depth
C. Its depth is thrice the breadth
D. Its breadth is thrice the depth
Answer : B

14. When the Mach number is more than 6, the flow is called
A. Sub-sonic flow
B. Sonic flow
C. Super-sonic flow
D. Hyper-sonic flow
Answer : D

15. 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

16. An error of 1% in measuring head over the crest 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

17. The hydraulic mean depth for a circular pipe of diameter (d) is
A. d/6
B. d/4
C. d/2
D. d
Answer : B

18. The hydraulic mean depth or the hydraulic radius is the ratio of
A. Area of flow and wetted perimeter
B. Wetted perimeter and diameter of pipe
C. Velocity of flow and area of flow
D. None of these
Answer : A

19. Which of the following is the unit of kinematic viscosity?
A. Pascal
B. Poise
C. Stoke
D. Faraday
Answer : C

20. The velocity of the liquid flowing through the divergent portion of a Venturimeter
A. Remains constant
B. Increases
C. Decreases
D. Depends upon mass of liquid
Answer : C

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

23. One litre of water occupies a volume of
A. 100 cm³
B. 250 cm³
C. 500 cm³
D. 1000 cm³
Answer : A

24. A manometer is used to measure
A. Atmospheric pressure
B. Pressure in pipes and channels
C. Pressure in Venturimeter
D. Difference of pressures between two points in a pipe
Answer : B

25. The pressure of air __________ with the increase of height from the surface of the earth.
A. Does not change
B. Decreases
C. Increases
D. None of these
Answer : B

26. The pressure measured with the help of a pressure gauge is called
A. Atmospheric pressure
B. Gauge pressure
C. Absolute pressure
D. Mean pressure
Answer : B

27. For pipes, laminar flow occurs when Reynolds number is
A. Less than 2000
B. Between 2000 and 4000
C. More than 4000
D. Less than 4000
Answer : A

28. The discharge over a rectangular notch is (where b = Width of notch, and H = Height of liquid, above the sill of the notch)
A. (2/3) C_d × b × ?(2gH)
B. (2/3) C_d × b × ?(2g) × H
C. (2/3) C_d × b × ?(2g) × H^3/2
D. (2/3) C_d × b × ?(2g) × H²
Answer : C

29. The product of mass and acceleration of flowing liquid is called
A. Inertia force
B. Viscous force
C. Gravity force
D. Pressure force
Answer : A

30. Coefficient of velocity is defined as the ratio of
A. Actual velocity of jet at vena contracta to the theoretical velocity
B. Area of jet at vena contracta to the area of orifice
C. Actual discharge through an orifice to the theoretical discharge
D. None of the above
Answer : A

31. Operation of McLeod gauge used for low pressure measurement is based on the principle of
A. Gas law
B. Boyle's law
C. Charles law
D. Pascal's law
Answer : B

32. A compound pipe of diameter d1, d2 and d3 having lengths l1, l2 and l3 is to be replaced by an equivalent pipe of uniform diameter d and of the same length (l) as that of the compound pipe. The size of the equivalent pipe is given by
A. l/d² = (l?/d?²) + (l?/d?²) + (l?/d?²)
B. l/d³ = (l?/d?³) + (l?/d?³) + (l?/d?³)
C. l/d? = (l?/d??) + (l?/d??) + (l?/d??)
D. l/d? = (l?/d??) + (l?/d??) + (l?/d??)
Answer : D

33. A square surface 3 m × 3 m lies in a vertical line in water pipe its upper edge at water surface. The hydrostatic force on square surface is
A. 9,000 kg
B. 13,500 kg
C. 18,000 kg
D. 27,000 kg
Answer : B

34. 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

35. Bulk modulus of a fluid is the ratio of
A. Shear stress to shear strain
B. Increase in volume to the viscosity of fluid
C. Increase in pressure to the volumetric strain
D. Critical velocity to the viscosity of fluid
Answer : C

36. 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

37. The specific weight of water is 1000 kg/m3
A. At normal pressure of 760 mm
B. At 4°C temperature
C. At mean sea level
D. All the above
Answer : D

38. According to equation of continuity,
A. w₁a₁ = w₂a₂
B. w₁v₁ = w₂v₂
C. a₁v₁ = a₂v₂
D. a₁/v₁ = a₂/v₂
Answer : C

39. Alcohol is used in manometers because
A. It has low vapour pressure
B. It is clearly visible
C. It has low surface tension
D. It can provide longer column due to low density
Answer : D

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

41. In one dimensional flow, the flow
A. Is steady and uniform
B. Takes place in straight line
C. Takes place in curve
D. Takes place in one direction
Answer : B

42. A piece of wood having weight 5 kg floats in water with 60% of its volume under the liquid. The specific gravity of wood is
A. 0.83
B. 0.6
C. 0.4
D. 0.3
Answer : B

43. An internal mouthpiece is said to be running free if the length of the mouthpiece is __________ the diameter of the orifice.
A. Less than twice
B. More than twice
C. Less than three times
D. More than three times
Answer : C

44. In a lock-gate, the reaction between two gates is (where P = Resultant pressure on the lock gate, and ? = Inclination of the gate with the normal to the side of the lock)
A. p/sin?
B. 2p/sin?
C. p/2sin?
D. 2p/sin (?/2)
Answer : C

45. The diameter of the nozzle (d) for maximum transmission of power is given by (where D = Diameter of pipe, f = Darcys coefficient of friction for pipe, and l = Length of pipe)
A. d = (D?/8fl)^1/2
B. d = (D?/8fl)^1/3
C. d = (D?/8fl)^1/4
D. d = (D?/8fl)^1/5
Answer : C

46. The hydraulic gradient line lies over the centre line of the pipe by an amount equal to the
A. Pressure head
B. Velocity head
C. Pressure head + velocity head
D. Pressure head - velocity head
Answer : A

47. Working principle of dead weight pressure gauge tester is based on
A. Pascal's law
B. Dalton's law of partial pressure
C. Newton's law of viscosity
D. Avogadro's hypothesis
Answer : A

48. 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

49. An object having 10 kg mass weighs 9.81 kg on a spring balance. The value of 'g' at this place is
A. 10 m/sec²
B. 9.81 m/sec²
C. 9.75 m/sec²
D. 9 m/sec
Answer : A

50. An open tank containing liquid is moving with an acceleration on an inclined plane. The inclination of the free surface of the liquid will be __________ to the acceleration of the tank.
A. Equal to
B. Directly proportional
C. Inversely proportional
D. None of these
Answer : B