Fluid Mechanics MCQ Solved Paper for IBPS Clerk

1. The absolute pressure is equal to
A. Gauge pressure + atmospheric pressure
B. Gauge pressure - atmospheric pressure
C. Atmospheric pressure - gauge pressure
D. Gauge pressure - vacuum pressure
Answer : A

2. The centre of gravity of the volume of the liquid displaced by an immersed body is called
A. Centre of gravity
B. Centre of pressure
C. Metacentre
D. Centre of buoyancy
Answer : D

3. The process of diffusion of one liquid into the other through a semi permeable membrane is called
A. Viscosity
B. Osmosis
C. Surface tension
D. Cohesion
Answer : B

4. The discharge of a depressed nappe is 6 to 7 percent __________ that of a free nappe.
A. Less than
B. More than
C. Equal to
D. None of these
Answer : B

5. A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm² and a volume of 0.039 m3 at 150 kg/cm². The bulk modulus of elasticity of liquid is
A. 400 kg/cm²
B. 4000 kg/cm²
C. 40 × 10? kg/cm²
D. 40 × 10? kg/cm²
Answer : B

6. 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

7. Froude's number is the ratio of inertia force to
A. Pressure force
B. Elastic force
C. Gravity force
D. Surface tension force
Answer : C

8. Which of the following meters is not associated with viscosity?
A. Red wood
B. Say bolt
C. Engler
D. Orsat
Answer : D

9. General energy equation holds for
A. Steady flow
B. Turbulent flow
C. Laminar flow
D. Non-uniform flow
Answer : D

10. The center of pressure of a surface subjected to fluid pressure is the point
A. On the surface at which resultant pressure acts
B. On the surface at which gravitational force acts
C. At which all hydraulic forces meet
D. Similar to metacentre
Answer : A

11. A piece weighing 3 kg in air was found to weigh 2.5 kg when submerged in water. Its specific gravity is
A. 1
B. 5
C. 7
D. 6
Answer : D

12. The flow in which conditions do not change with time at any point, is known as
A. One dimensional flow
B. Uniform flow
C. Steady flow
D. Turbulent flow
Answer : C

13. 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

14. A fluid in equilibrium can't sustain
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Bending stress
Answer : C

15. Coefficient of resistance is 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. Loss of head in the orifice to the head of water available at the exit of the orifice
D. Actual discharge through an orifice to the theoretical discharge
Answer : C

16. Surface tension
A. Acts in the plane of the interface normal to any line in the surface
B. Is also known as capillarity
C. Is a function of the curvature of the interface
D. Decreases with fall in temperature
Answer : A

17. The kinematic viscosity is the
A. Ratio of absolute viscosity to the density of the liquid
B. Ratio of density of the liquid to the absolute viscosity
C. Product of absolute viscosity and density of the liquid
D. Product of absolute viscosity and mass of the liquid
Answer : A

18. The discharge through a large rectangular orifice is given by (where H1 = Height of the liquid above the top of the orifice, H2 = Height of the liquid above the bottom of the orifice, b = Breadth of the orifice, and Cd = Coefficient of discharge)
A. Q = (2/3) Cd × b × ?(2g) × (H2 - H1)
B. Q = (2/3) Cd × b × ?(2g) × (H2 ^1/2 - H1 ^1/2)
C. Q = (2/3) Cd × b × ?(2g) × (H2 ^3/2 - H1 ^3/2)
D. Q = (2/3) Cd × b × ?(2g) × (H2 ² - H1 ²)
Answer : C

19. A bucket of water is hanging from a spring balance. An iron piece is suspended into water without touching sides of bucket from another support. The spring balance reading will
A. Increase
B. Decrease
C. Remain same
D. Increase/decrease depending on depth of immersion
Answer : C

20. Viscous force is the __________ of shear stress due to viscosity and cross-section area of flow.
A. Sum
B. Different
C. Product
D. Ratio
Answer : C

21. The Reynold's number of a ship is __________ to its velocity and length.
A. Directly proportional
B. Inversely proportional
C. Square root of velocity
D. None of these
Answer : A

22. A flow whose streamline is represented by a straight line, is called __________ dimensional flow.
A. One
B. Two
C. Three
D. Four
Answer : A

23. 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

24. An ideal flow of any fluid must satisfy
A. Pascal law
B. Newton's law of viscosity
C. Boundary layer theory
D. Continuity equation
Answer : D

25. The line of action of the buoyant force acts through the Centroid of the
A. Submerged body
B. Volume of the floating body
C. Volume of the fluid vertically above the body
D. Displaced volume of the fluid
Answer : D

26. The density of water is 1000 kg/m3 at
A. 0° C
B. 0° K
C. 4° C
D. 20° C
Answer : C

27. Density of water is maximum at
A. 0° C
B. 0° K
C. 4° C
D. 100° C
Answer : C

28. When a liquid is flowing through a pipe, the velocity of the liquid is
A. Maximum at the centre and minimum near the walls
B. Minimum at the centre and maximum near the walls
C. Zero at the centre and maximum near the walls
D. Maximum at the centre and zero near the walls
Answer : A

29. The length of a liquid stream while flowing over a weir __________ at the ends of the sill.
A. Expands
B. Does not change
C. Contracts
D. None of these
Answer : C

30. 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

31. A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. The total pressure on the wall acts at a distance __________ from the liquid surface.
A. H/3
B. H/2
C. 2H/3
D. 3H/4
Answer : C

32. The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to
A. 1/2 × depth
B. 1/2 × breadth
C. 1/2 × sloping side
D. 1/4 × (depth + breadth)
Answer : A

33. Barometer is used to measure
A. Velocity of liquid
B. Atmospheric pressure
C. Pressure in pipes and channels
D. Difference of pressure between two points in a pipe
Answer : B

34. 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

35. Buoyant force is
A. Resultant force acting on a floating body
B. Equal to the volume of liquid displaced
C. Force necessary to keep a body in equilibrium
D. The resultant force on a body due to the fluid surrounding it
Answer : D

36. The power transmitted through the nozzle is maximum when the head lost due to friction in the pipe is __________ of the total supply head.
A. One-half
B. One-third
C. Two-third
D. None of these
Answer : B

37. Differential manometer is used to measure
A. Pressure in pipes, channels etc.
B. Atmospheric pressure
C. Very low pressure
D. Difference of pressure between two points
Answer : D

38. The discharge over a rectangular notch is
A. Inversely proportional to H^3/2
B. Directly proportional to H^3/2
C. Inversely proportional to H^5/2
D. Directly proportional to H^5/2
Answer : B

39. 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

40. When a plate is immersed in a liquid parallel to the flow, it will be subjected to a pressure __________ that if the same plate is immersed perpendicular to the flow.
A. Less than
B. More than
C. Equal to
D. None of these
Answer : A

41. Rain drops are spherical because of
A. Viscosity
B. Air resistance
C. Surface tension forces
D. Atmospheric pressure
Answer : C

42. Flow occurring in a pipeline when a valve is being opened is
A. Steady
B. Unsteady
C. Laminar
D. Vortex
Answer : B

43. 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

44. Liquids transmit pressure equally in all the directions. This is according to
A. Boyle's law
B. Archimedes principle
C. Pascal's law
D. Newton's formula
Answer : C

45. A nozzle is generally made of
A. Cylindrical shape
B. Convergent shape
C. Divergent shape
D. Convergent-divergent shape
Answer : B

46. If the depth of water in an open channel is less than the critical depth, the flow is called
A. Critical flow
B. Turbulent flow
C. Tranquil flow
D. Torrential flow
Answer : D

47. To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than
A. 2.4 m above the hydraulic gradient
B. 6.4 m above the hydraulic gradient
C. 10.0 m above the hydraulic gradient
D. 5.0 above the hydraulic gradient
Answer : B

48. The resultant upward pressure of a fluid on a floating body is equal to the weight of the fluid displaced by the body. This definition is according to
A. Buoyancy
B. Equilibrium of a floating body
C. Archimedes' principle
D. Bernoulli's theorem
Answer : C

49. A tank of uniform cross-sectional area (A) containing liquid upto height (H1) has an orifice of cross-sectional area (a) at its bottom. The time required to bring the liquid level from H1 to H2 will be
A. 2A × ?H?/C_d × a × ?(2g)
B. 2A × ?H?/C_d × a × ?(2g)
C. 2A × (?H? - ?H?)/C_d × a × ?(2g)
D. 2A × (?H^3/2 - ?H3/2)/C_d × a × ?(2g)
Answer : C

50. Poise is the unit of
A. Surface tension
B. Capillarity
C. Viscosity
D. Shear stress in fluids
Answer : C