Fluid Mechanics MCQ Solved Paper for NEET PG

1. Dynamic viscosity of most of the liquids with rise in temperature
A. Increases
B. Decreases
C. Remain unaffected
D. Unpredictable
Answer : B

2. The specific weight of water in S.I. units is taken as
A. 9.81 kN/m³
B. 9.81 × 10³ N/m³
C. 9.81 × 10^-6 N/mm³
D. Any one of these
Answer : D

3. The theoretical velocity of jet at vena contracta is (where H = Head of water at vena contracta)
A. 2gH
B. H × ?(2g)
C. 2g × ?H
D. ?(2gh)
Answer : D

4. The body will float if the force of buoyancy is __________ the weight of the liquid displaced.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : C

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

6. 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

7. Two pipe systems can be said to be equivalent, when the following quantities are same
A. Friction loss and flow
B. Length and diameter
C. Flow and length
D. Friction factor and diameter
Answer : A

8. A flow through a long pipe at constant rate is called
A. Steady uniform flow
B. Steady non-uniform flow
C. Unsteady uniform flow
D. Unsteady non-uniform flow
Answer : A

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

10. Falling drops of water become spheres due to the property of
A. Adhesion
B. Cohesion
C. Surface tension
D. Viscosity
Answer : C

11. 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

12. The height of a water column equivalent to a pressure of 0.15 MPa is
A. 15.3 m
B. 25.3 m
C. 35.3 m
D. 45.3 m
Answer : A

13. A body floating in a liquid is said to be in neutral equilibrium, if its metacentre
A. Coincides with its centre of gravity
B. Lies above its centre of gravity
C. Lies below its centre of gravity
D. Lies between the centre of buoyancy and centre of gravity
Answer : A

14. Which of the following instrument can be used for measuring speed of a submarine moving in deep sea?
A. Venturimeter
B. Orifice plate
C. Hot wire anemometer
D. Pitot tube
Answer : D

15. The horizontal component of buoyant force is
A. Negligible
B. Same as buoyant force
C. Zero
D. None of the above
Answer : C

16. The line of action of the buoyant force acts through the
A. Centroid of the volume of fluid vertically above the body
B. Centre of the volume of floating body
C. Center of gravity of any submerged body
D. Centroid of the displaced volume of fluid
Answer : D

17. 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

18. The viscosity of water is __________ than that of mercury.
A. Higher
B. Lower
C. Same as
D. None of these
Answer : A

19. 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

20. The meatcentric height of a ship is 0.6 m and the radius of gyration is 4 m. The time of rolling of a ship is
A. 4.1 s
B. 5.2 s
C. 10.4 s
D. 14.1 s
Answer : C

21. A fluid whose viscosity does not change with the rate of deformation or shear strain is known as
A. Real fluid
B. Ideal fluid
C. Newtonian fluid
D. Non-Newtonian fluid
Answer : C

22. 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
Anser : C

23. Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the
A. Force of adhesion
B. Force of cohesion
C. Force of friction
D. Force of diffusion
Answer : B

24. In a static fluid
A. Resistance to shear stress is small
B. Fluid pressure is zero
C. Linear deformation is small
D. Only normal stresses can exist
Answer : D

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

26. According to Bernoulli's equation
A. Z + p/w + v²/2g = constant
B. Z + p/w - v²/2g = constant
C. Z - p/w + v²/2g = constant
D. Z - p/w - v²/2g = constant
Answer : A

27. The coefficient of viscosity may be determined by
A. Capillary tube method
B. Orifice type viscometer
C. Rotating cylinder method
D. All of these
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 loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v = Velocity of the liquid in the pipe, ? = Viscosity of the liquid, and w = Specific weight of the flowing liquid)
A. 4?vl/wd²
B. 8?vl/wd²
C. 16?vl/wd²
D. 32?vl/wd²
Answer : D

30. 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

31. The specific gravity of an oil whose specific weight is 7.85 kN/m3, is
A. 0.8
B. 1
C. 1.2
D. 1.6
Answer : A

32. 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

33. A compound pipe is required to be replaced by a new pipe. The two pipes are said to be equivalent, if
A. Length of both the pipes is same
B. Diameter of both the pipes is same
C. Loss of head and discharge of both the pipes is same
D. Loss of head and velocity of flow in both the pipes is same
Answer : C

34. 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

35. The loss of head at entrance in a pipe is (where v = Velocity of liquid in the pipe)
A. v²/2g
B. 0.5v²/2g
C. 0.375v²/2g
D. 0.75v²/2g
Answer : B

36. The loss of head due to friction in a pipe of uniform diameter in which a viscous flow is taking place, is (where RN = Reynold number)
A. 1/R_N
B. 4/R_N
C. 16/R_N
D. 64/R_N
Answer : C

37. A moving fluid mass may be brought to a static equilibrium position, by applying an imaginary inertia force of the same magnitude as that of the accelerating force but in the opposite direction. This statement is called
A. Pascal's law
B. Archimedess principle
C. D-Alembert's principle
D. None of these
Answer : C

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

39. 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

40. The variation in the volume of a liquid with the variation of pressure is called its
A. Surface tension
B. Compressibility
C. Capillarity
D. Viscosity
Answer : B

41. When the flow in an open channel is gradually varied, the flow is said to be
A. Steady uniform flow
B. Steady non-uniform flow
C. Unsteady uniform flow
D. Unsteady non-uniform flow
Answer : B

42. Pressure of the order of 10 torr can be measured by
A. Bourdon tube
B. Pirani Gauge
C. Micro-manometer
D. Lonisation gauge
Answer : D

43. 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

44. A glass tube of small diameter (d) is dipped in fluid. The height of rise or fall in the tube given by (where w = Specific weight of liquid, ? = Angle of contact of the liquid surface, and ? = Surface tension)
A. 4wd/? cos?
B. ? cos?/4wd
C. 4? cos?/wd
D. wd/4? cos?
Answer : C

45. 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

46. 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

47. In an isothermal atmosphere, the pressure
A. Decreases linearly with elevation
B. Remain constant
C. Varies in the same way as the density
D. Increases exponentially with elevation
Answer : C

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

49. The weight per unit volume of a liquid at a standard temperature and pressure is called
A. Specific weight
B. Mass density
C. Specific gravity
D. None of these
Answer : A

50. The unit of surface tension is
A. N/m
B. N/m²
C. N/m³
D. N-m
Answer : A