Fluid Mechanics 1000+ MCQ with answer for IBPS SO

1. Barometer 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 : B

2. 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

3. A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. Which of the following statement is correct?
A. The pressure on the wall at the liquid level is minimum
B. The pressure on the bottom of the wall is maximum
C. The pressure on the wall at the liquid level is zero, and on the bottom of the wall is maximum
D. The pressure on the bottom of the wall is zer
Answer : C

4. A fluid which obeys the Newton's law of viscosity is termed as
A. Real fluid
B. Ideal fluid
C. Newtonian fluid
D. Non-Newtonian fluid
Answer : C

5. In a short cylindrical external mouthpiece, the vena contracta occurs at a distance __________ the diameter of the orifice from the outlet of orifice.
A. Equal to
B. One-fourth
C. One-third
D. One-half
Answer : B

6. 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

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

8. A streamline is defined as the line
A. Parallel to central axis flow
B. Parallel to outer surface of pipe
C. Of equal velocity in a flow
D. Along which the pressure drop is uniform
Answer : C

9. 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

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

11. 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

12. Select the correct statement
A. Local atmospheric pressure depends upon elevation of locality only
B. Standard atmospheric pressure is the mean local atmospheric pressure a* sea level
C. Local atmospheric pressure is always below standard atmospheric pressure
D. A barometer reads the difference between local and standard atmospheric pressure
Answer : B

13. The rise or depression of liquid in a tube due to surface tension will increase in size of tube will
A. Increase
B. Remain unaffected
C. May increase or decrease depending on the characteristics of liquid
D. Decrease
Answer : D

14. Gauge pressure at a point is equal to the absolute pressure __________ the atmospheric pressure.
A. Plus
B. Minus
C. Divide
D. Multiply
Answer : B

15. Newton's law of viscosity is a relationship between
A. Pressure, velocity and temperature
B. Shear stress and rate of shear strain
C. Shear stress and velocity
D. Rate of shear strain and temperature
Answer : B

16. 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

17. 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

18. If a body floating in a liquid occupies a new position and remains at rest in this new position, when given a small angular displacement, the body is said to be in __________ equilibrium.
A. Neutral
B. Stable
C. Unstable
D. None of these
Answer : A

19. 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

20. 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

21. Surface energy per unit area of a surface is numerically equal to
A. Atmospheric pressure
B. Surface tension
C. Force of adhesion
D. Force of cohesion
Answer : B

22. A uniform body 3 m long, 2 m wide and 1 m deep floats in water. If the depth of immersion is 0.6 m, then the weight of the body is
A. 3.53 kN
B. 33.3 kN
C. 35.3 kN
D. None of these
Answer : C

23. 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

24. The total pressure on an immersed surface inclined at an angle ? with the liquid surface is
A. wA
B. wx
C. wAx
D. wAx/sin?
Answer : C

25. The volume of a fluid __________ as the pressure increases.
A. Remains same
B. Decreases
C. Increases
D. None of these
Answer : B

26. The property of a liquid which offers resistance to the movement of one layer of liquid over another adjacent layer of liquid, is called
A. Surface tension
B. Compressibility
C. Capillarity
D. Viscosity
Answer : D

27. The units of dynamic or absolute viscosity are
A. Metres² per sec
B. kg sec/meter
C. Newton-sec per meter
D. Newton-sec² per meter
Answer : C

28. Center of pressure on an inclined plane is
A. At the Centroid
B. Above the Centroid
C. Below the Centroid
D. At metacentre
Answer : C

29. The power absorbed (in watts) in overcoming the viscous resistance of a footstep bearing is
A. ? ?³ N² R² /1800 t
B. ? ?³ N² R? /1800 t
C. ? ?³ N² R² /3600 t
D. ? ?³ N² R? /3600 t
Answer : B

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

31. Bulk modulus of a fluid __________ as the pressure increases.
A. Remain same
B. Decreases
C. Increases
D. None of these
Answer : C

32. In order to avoid tendency of separation at throat in a Venturimeter, the ratio of the diameter at throat to the diameter of pipe should be
A. 1/16 to 1/8
B. 1/8 to 1/4
C. 1/4 to 1/3
D. 1/3 to 1/2
Answer : D

33. The velocity at which the flow changes from laminar flow to turbulent flow is called
A. Critical velocity
B. Velocity of approach
C. Sub-sonic velocity
D. Super-sonic velocity
Answer : A

34. The resultant of all normal pressures acts
A. At C.G. of body
B. At center of pressure
C. Vertically upwards
D. At metacentre
Answer : C

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

36. Viscosity of water in comparison to mercury is
A. Higher
B. Lower
C. Same
D. Higher/lower depending on temperature
Answer : A

37. An open vessel of water is accelerated up an inclined plane. The free water surface will
A. Be horizontal
B. Make an angle in direction of inclination of inclined plane
C. Make an angle in opposite direction to inclination of inclined plane
D. Any one of above is possible
Answer : C

38. The power transmitted through the pipe is maximum when the head lost due to friction is equal to
A. One-fourth of the total supply head
B. One-third of the total supply head
C. One-half of the total supply head
D. Two-third of the total supply head
Answer : B

39. The resultant upward pressure of the fluid on an immersed body due to its tendency to uplift the submerged body is called
A. Up-thrust
B. Reaction
C. Buoyancy
D. Metacentre
Answer : C

40. Hot wire anemometer is used to measure
A. Pressure in gases
B. Liquid discharge
C. Pressure in liquids
D. Gas velocities
Answer : D

41. 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

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

43. An average value of coefficient of velocity is
A. 0.62
B. 0.76
C. 0.84
D. 0.97
Answer : D

44. An orifice is said to be large, if
A. The size of orifice is large
B. The velocity of flow is large
C. The available head of liquid is more than 5 times the height of orifice
D. The available head of liquid is less than 5 times the height of orifice
Answer : D

45. All the terms of energy in Bernoulli's equation have dimension of
A. Energy
B. Work
C. Mass
D. Length
Answer : D

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

47. Water is a __________ fluid.
A. Real
B. Ideal
C. Newtonian
D. Non-Newtonian
Answer : C

48. 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

49. For hypersonic flow, the Mach number is
A. Unity
B. Greater than unity
C. Greater than 2
D. Greater than 4
Answer : D

50. 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