Fluid Mechanics MCQ Solved Paper for ESIC

1. According to Manning's formula, the discharge through an open channel is (where M = Manning's constant)
A. A × M × m^1/2 × i^2/3
B. A × M × m^2/3 × i^1/2
C. A^1/2 × M^2/3 × m × i
D. A^2/3 × M^1/3 × m × i
Answer : B

2. Free surface of a liquid tends to contract to the smallest possible area due to force of
A. Surface tension
B. Viscosity
C. Friction
D. Cohesion
Answer : A

3. When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure
A. Varies as the square of the radial distance
B. Increases linearly as its radial distance
C. Increases as the square of the radial distance
D. Decreases as the square of the radial distance
Answer : A

4. A metal with specific gravity of a floating in a fluid of same specific gravity a will
A. Sink to bottom
B. Float over fluid
C. Partly immersed
D. Be fully immersed with top surface at fluid surface
Answer : D

5. A pressure of 25 m of head of water is equal to
A. 25 kN/ m²
B. 245 kN/ m²
C. 2500 kN/m²
D. 2.5 kN/ m²
Answer : B

6. 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

7. 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

8. 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

9. The two important forces for a floating body are
A. Buoyancy, gravity
B. Buoyancy, pressure
C. Buoyancy, inertial
D. Inertial, gravity
Answer : A

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. The total pressure on the top of a closed cylindrical vessel completely filled up with a liquid is
A. Directly proportional to (radius)²
B. Inversely proportional to (radius)²
C. Directly proportional to (radius)⁴
D. Inversely proportional to (radius)⁴
Answer : C

12. Choose the wrong statement
A. Fluids are capable of flowing
B. Fluids conform to the shape of the containing vessels
C. When in equilibrium, fluids cannot sustain tangential forces
D. When in equilibrium, fluids can sustain shear forces
Answer : D

13. 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

14. Which of the following instrument can be used for measuring speed of an aeroplane?
A. Venturimeter
B. Orifice plate
C. Pitot tube
D. Rotameter
Answer : C

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

16. 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

17. A point, in a compressible flow where the velocity of fluid is zero, is called
A. Critical point
B. Vena contracta
C. Stagnation point
D. None of these
Answer : C

18. 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

19. The region between the separation streamline and the boundary surface of the solid body is known as
A. Wake
B. Drag
C. Lift
D. Boundary layer
Answer : A

20. In a forced vortex, the velocity of flow everywhere within the fluid is
A. Maximum
B. Minimum
C. Zero
D. Nonzero finite
Answer : D

21. 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

22. The flow in which each liquid particle has a definite path and their paths do not cross each other is called
A. One dimensional flow
B. Streamline flow
C. Steady flow
D. Turbulent flow
Answer : B

23. 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

24. 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

25. When a body is placed over a liquid, it will float if
A. Gravitational force is equal to the up-thrust of the liquid
B. Gravitational force is less than the up-thrust of the liquid
C. Gravitational force is more than the up-thrust of the liquid
D. None of the above
Answer : B

26. If a body floating in a liquid returns back to its original position, when given a small angular displacement, the body is said to be in
A. Neutral equilibrium
B. Stable equilibrium
C. Unstable equilibrium
D. None of these
Answer : B

27. The liquid used in manometers should have
A. Low density
B. High density
C. Low surface tension
D. High surface tension
Answer : D

28. 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

29. The point at which the resultant pressure on an immersed surface acts, is known as
A. Centre of gravity
B. Centre of depth
C. Centre of pressure
D. Centre of immersed surface
Answer : C

30. Reynolds number is significant in
A. Supersonics, as with projectile and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with ship's hulls
D. All of the above
Answer : B

31. 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

32. A flow in which the quantity of liquid flowing per second is constant, is called __________ flow.
A. Steady
B. Streamline
C. Turbulent
D. Unsteady
Answer : A

33. 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

34. The intensity of pressure at any point, in a liquid, is
A. Directly proportional to the area of the vessel containing liquid
B. Directly proportional to the depth of liquid from the surface
C. Directly proportional to the length of the vessel containing liquid
D. Inversely proportional to the depth of liquid from the surface
Answer : B

35. 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

36. 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

37. The force exerted by a moving fluid on an immersed body is directly proportional to the rate of change of momentum due to the presence of the body. This statement is called
A. Newton's law of motion
B. Newton's law of cooling
C. Newton's law of viscosity
D. Newton's law of resistance
Answer : D

38. The flow of water through the hole in the bottom of a wash basin is an example of
A. Steady flow
B. Uniform flow
C. Free vortex
D. Forced vortex
Answer : C

39. 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

40. The total energy of each particle at various places in the case of perfect incompressible fluid flowing in continuous stream
A. Keeps on increasing
B. Keeps on decreasing
C. Remain constant
D. May increase/decrease
Answer : C

41. 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

42. An internal mouthpiece is said to be running __________ if the length of the mouthpiece is more than three times the diameter of the orifice.
A. Free
B. Partially
C. Full
D. None of these
Answer : C

43. 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

44. 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

45. 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

46. The discharge through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.
A. 0.34 times
B. 0.67 times
C. 0.81 times
D. 0.95 times
Answer : D

47. 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 empty the tank completely will be
A. (2A?H?)/(C_d × a?2g)
B. (2AH?)/(C_d × a?2g)
C. (2AH?^3/2)/(C_d × a?2g)
D. (2AH?²)/(C_d × a?2g)
Answer : A

48. A hydraulic press has a ram of 15 cm diameter and plunger of 1.5 cm. It is required to lift a weight of 1 tonne. The force required on plunger is equal to
A. 10 kg
B. 100 kg
C. 1000 kg
D. 1 kg
Answer : A

49. Choose the wrong statement
A. The center of buoyancy is located at the center of gravity of the displaced liquid
B. For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy
C. If C.G. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions
D. All floating bodies are stable
Answer : D

50. 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