MCQOPTIONS
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MCQOPTIONS
This section includes 59 Mcqs, each offering curated multiple-choice questions to sharpen your Fluid Mechanics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A liquid is flowing at 11,400 l.h-1 along a pipeline having a diameter of 4 cm. If the liquid has a density of 1 g.ml-1 and viscosity of 0.001kg.m-1.s-1, then the liquid would be in the |
| A. | laminar phase |
| B. | transient phase |
| C. | turbulent phase |
| D. | any of the phase |
| Answer» D. any of the phase | |
| 2. |
A stirred tank reactor containing a fluid with a density of 2.5 g.ml-1 and viscosity of 0.002 kg m-1s-1 is mixed at 120 rpm. If the fluid is mixed with an impeller having diameter 50 cm, then the Reynolds number of the liquid in the reactor is |
| A. | 2500 |
| B. | 100 |
| C. | 12,50,000 |
| D. | 1,000,000 |
| Answer» D. 1,000,000 | |
| 3. |
Three flows named as 1,2 and 3 are observed. The Reynold’s number for the three are 100, 1000 and 10000. Which of the flows will be laminar? |
| A. | only 1 |
| B. | only 1 and 2 |
| C. | 1, 2 and 3 |
| D. | only 3 |
| Answer» C. 1, 2 and 3 | |
| 4. |
“The velocity of entrance and exit through a nozzle remains the same.” Is this ever possible? |
| A. | only if the flow is compressible |
| B. | only if the flow is laminar |
| C. | only if the flow is rotational |
| D. | never possible |
| Answer» B. only if the flow is laminar | |
| 5. |
A beaker contains water up to a certain height as shown. If the water is allowed to get discharged through a small diffuser, what type of flow will it be in the pipe? |
| A. | steady and uniform |
| B. | unsteady and uniform |
| C. | steady and non-uniform |
| D. | unsteady and non-uniform |
| Answer» E. | |
| 6. |
A beaker contains water up to a certain height as shown. If the water is allowed to get discharged through a small nozzle, what type of flow will it be in the pipe? |
| A. | steady and uniform |
| B. | unsteady and uniform |
| C. | steady and non-uniform |
| D. | unsteady and non-uniform |
| Answer» E. | |
| 7. |
A beaker contains water up to a certain height as shown. If the water is allowed to get discharged through a small pipe (of a uniform diameter), what type of flow will it be in the pipe? |
| A. | steady and uniform |
| B. | unsteady and uniform |
| C. | steady and non-uniform |
| D. | unsteady and non-uniform |
| Answer» C. steady and non-uniform | |
| 8. |
The viscosity of a fluid increases with the length of time that it is being mixed. This fluid would be best described as being |
| A. | newtonian |
| B. | rheopectic |
| C. | viscoelastic |
| D. | thixotropic |
| Answer» C. viscoelastic | |
| 9. |
Mixing in stirred tank reactors can |
| A. | be described as either laminar, transient or turbulent |
| B. | achieve turbulent conditions by increasing the stirrer speed |
| C. | induce laminar flow conditions by the addition of baffles |
| D. | all of the above |
| Answer» B. achieve turbulent conditions by increasing the stirrer speed | |
| 10. |
In animal cell bioreactor, bubble damage can be minimized by |
| A. | the addition of a shear protectorant |
| B. | using a bubble free oxygen delivery system |
| C. | headspace aeration |
| D. | all of the above |
| Answer» E. | |
| 11. |
The SI unit for viscosity is |
| A. | kg.m¹.s¹ |
| B. | kg.m².s² |
| C. | kg.m³.s¹ |
| D. | kg.m¹.s² |
| Answer» B. kg.m².s² | |
| 12. |
A thixotropic fluid is one in which the viscosity |
| A. | is constant regardless of the stirrer speed or mixing time |
| B. | changes during mixing but returns to its original state after mixing |
| C. | increases with mixing time |
| D. | decreases with mixing time |
| Answer» E. | |
| 13. |
The viscosity of a fluid increases with increasing stirrer speed. This fluid would be best described as being |
| A. | newtonian |
| B. | pseudoplastic |
| C. | dilatant |
| D. | thixotropic |
| Answer» D. thixotropic | |
| 14. |
A rheopectic fluid is one in which the viscosity |
| A. | is constant regardless of the stirrer speed or mixing time |
| B. | changes during mixing but returns to its original state after mixing |
| C. | increases with mixing time |
| D. | decreases with mixing time |
| Answer» D. decreases with mixing time | |
| 15. |
If the viscosity of a fluid decreases with the length of time that it is being mixed, then this fluid is |
| A. | newtonian |
| B. | rheopectic |
| C. | viscoelastic |
| D. | thixotropic |
| Answer» E. | |
| 16. |
Which of the following describes the importance of the Kolmogorov eddy size in the biotechnology? |
| A. | The Kolmogorov eddy size is a measure of the smallest eddy size in a liquid |
| B. | When the Kolmogorov eddy size become equivalent or smaller than the cell or particle diameter, then the cell or particle will become susceptible to shear damage |
| C. | At the Kolmogorov eddy size, much of the energy of the originating eddy will be released |
| D. | All of the above |
| Answer» E. | |
| 17. |
Reynolds number for turbulent flow over a plate should be more than |
| A. | 5 x 10⁵ |
| B. | 10⁶ |
| C. | 5 x 10⁵ |
| D. | 500 |
| Answer» C. 5 x 10⁵ | |
| 18. |
A pseudoplastic fluid is one in which the viscosity |
| A. | is constant regardless of the stirrer speed or mixing time |
| B. | changes during mixing but returns to its original state after mixing |
| C. | increases with increasing stirrer speed |
| D. | decreases with increasing stirrer speed |
| Answer» E. | |
| 19. |
Water is a |
| A. | newtonian fluid |
| B. | pseudoplastic |
| C. | dilatant |
| D. | rheopectic |
| Answer» B. pseudoplastic | |
| 20. |
Which of the following affect the Kolmogorov eddy size? |
| A. | Stirrer speed |
| B. | Physical properties of the liquid |
| C. | Size and type of impeller |
| D. | All of these |
| Answer» E. | |
| 21. |
Bubble free aeration systems requires |
| A. | silicone tubing or gas permeable membranes to facilitate gas transfer |
| B. | carbon dioxide instead of air to supply oxygen |
| C. | silicone tubing or gas permeable membranes to remove carbon dioxide by oxygen in the form of hydrogen peroxide |
| D. | filled headspace of the reactor with carbon dioxide |
| Answer» B. carbon dioxide instead of air to supply oxygen | |
| 22. |
If the viscosity of a fluid decreases with increasing stirrer speed, then the nature of the fluid is |
| A. | newtonian |
| B. | pseudoplastic |
| C. | dilatant |
| D. | thixotropic |
| Answer» C. dilatant | |
| 23. |
Which of the following can act as a shear protectorant? |
| A. | Serum |
| B. | Silicone oil |
| C. | Glucose |
| D. | Glutamic acid |
| Answer» B. Silicone oil | |
| 24. |
Non-linear relationship between shear stress and shear rate exists in |
| A. | newtonian fluids |
| B. | non-newtonian fluids |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» C. both (a) and (b) | |
| 25. |
Filamentous fungal cells are more shear sensitive than bacterial cells because of |
| A. | the presence of citin in cell walls of filamentous fungi |
| B. | larger in size than bacterial cells and therefore are more susceptible to shear forces |
| C. | fungal cells are much larger than bacterial cells |
| D. | all of the above |
| Answer» E. | |
| 26. |
Which of the following describes the detrimental effect of bubbles on animal cells? |
| A. | Cells trapped on the surface of bubbles can be damaged when the bubbles explode, releasing their pressure and surface energies |
| B. | Cells trapped in the moving foam can be dragged apart by the bubbles |
| C. | Both (a) and (b) |
| D. | Bubbles can explode in the liquid medium causing the release of ultraviolet radiation |
| Answer» D. Bubbles can explode in the liquid medium causing the release of ultraviolet radiation | |
| 27. |
A fluid in which the viscosity decreases with increasing stirrer speed and mixing time, can be represented as |
| A. | newtonian fluid |
| B. | pseudoplastic, thixotropic fluid |
| C. | dilatant, rheopectic fluid |
| D. | dilatant, pseudoplastic fluid |
| Answer» C. dilatant, rheopectic fluid | |
| 28. |
A fluid in which the viscosity increases with increasing stirrer speed and mixing time can be called as |
| A. | newtonian fluid |
| B. | pseudoplastic, thixotropic fluid |
| C. | dilatant, rheopectic fluid |
| D. | dilatant pseudoplastic fluid |
| Answer» D. dilatant pseudoplastic fluid | |
| 29. |
The viscosity of water at STP is approximately |
| A. | 0.005 kg.m¹.s¹ |
| B. | 0.001 kg.m¹.s¹ |
| C. | 0.003 kg.m².s¹ |
| D. | 0.1 g.cm¹.s¹ |
| Answer» C. 0.003 kg.m².s¹ | |
| 30. |
Newtonian fluid is one in which the viscosity |
| A. | remains constant with time and power input |
| B. | increases with the level of power input |
| C. | decreases with the level of power input |
| D. | drastically increases with the level of power input |
| Answer» B. increases with the level of power input | |
| 31. |
A liquid is flowing at 11,400 l.h¹ along a pipeline having a diameter of 4 cm. If the liquid has a density of 1 g.ml¹ and viscosity of 0.001kg.m¹.s¹, then the liquid would be in the |
| A. | laminar phase |
| B. | transient phase |
| C. | turbulent phase |
| D. | any of the phase |
| Answer» D. any of the phase | |
| 32. |
The viscosity of a fluid changes with either stirrer speed or mixing time. But when mixing ceases, the viscosity returns to its original state. This fluid is best described as |
| A. | newtonian |
| B. | rheopectic |
| C. | viscoelastic |
| D. | thixotropic |
| Answer» D. thixotropic | |
| 33. |
A stirred tank reactor containing a fluid with a density of 2.5 g.ml¹ and viscosity of 0.002 kg m¹s¹ is mixed at 120 rpm. If the fluid is mixed with an impeller having diameter 50 cm, then the Reynolds number of the liquid in the reactor is |
| A. | 2500 |
| B. | 100 |
| C. | 12,50,000 |
| D. | 1,000,000 |
| Answer» D. 1,000,000 | |
| 34. |
A dilatant fluid is one in which the viscosity |
| A. | is constant regardless of the stirrer speed or mixing time |
| B. | changes during mixing but returns to its original state after mixing |
| C. | increases with increasing stirrer speed |
| D. | decreases with increasing stirrer speed |
| Answer» D. decreases with increasing stirrer speed | |
| 35. |
A viscoelastic fluid is one in which the viscosity |
| A. | is constant regardless of the stirrer speed or mixing time |
| B. | changes during mixing but returns to its original state after mixing |
| C. | increases with increasing stirrer speed |
| D. | decreases with increasing stirrer speed |
| Answer» C. increases with increasing stirrer speed | |
| 36. |
In sparged mammalian cell bioreactors, the cell damage is caused because of |
| A. | shear stress arising during mixing of the cell culture fluid |
| B. | shear stresses arising from the breakup of bubbles at the liquid surface |
| C. | shear stresses between bubbles in foam at the liquid surface |
| D. | all of the above |
| Answer» B. shear stresses arising from the breakup of bubbles at the liquid surface | |
| 37. |
Pluronic F68 protects mammalian cells from damage stems as it is a/an |
| A. | surface active agent which stabilizes foams |
| B. | surface active agent which destabilizes foams |
| C. | excellent source of vitamins |
| D. | coagulant |
| Answer» B. surface active agent which destabilizes foams | |
| 38. |
The medium will have the highest viscosity (considering that the cells do not secrete gums) with the presence of |
| A. | single celled bacteria |
| B. | filamentous fungi that form pellets |
| C. | filamentous fungi that grow as long poorly branched chains |
| D. | yeast |
| Answer» D. yeast | |
| 39. |
The viscous nature of a non-Newtonian fluid |
| A. | remains constant with time and power input |
| B. | changes with the level of power input and/or the length of time during which the fluid is mixed |
| C. | is similar to that of a perfect gas |
| D. | is similar to that of water |
| Answer» C. is similar to that of a perfect gas | |
| 40. |
The viscosity of liquid was classified as both dilatant and rheopectic, which means that the viscosity |
| A. | increased with stirring speed but decreased with mixing time |
| B. | increased with stirring speed and increased with mixing time |
| C. | decreased with stirring speed but increased with mixing time |
| D. | decreased with stirring speed and decreased with mixing time |
| Answer» C. decreased with stirring speed but increased with mixing time | |
| 41. |
Which of the following compound, if added to a solution will lead to the greatest increase in viscosity? |
| A. | A globular protein |
| B. | Glucose |
| C. | A long chain protein such as albumin |
| D. | Water |
| Answer» D. Water | |
| 42. |
A Brookfield viscometer measures viscosity by determining |
| A. | the shear stress |
| B. | the shear rate |
| C. | the shear stress and shear rate |
| D. | the torque required to move an impeller at a set speed |
| Answer» E. | |
| 43. |
Which of the following factors will affect the sensitivity of animal cells to shear conditions? |
| A. | Cell size |
| B. | Availability of nutrients in the medium |
| C. | The presence of shear protectorants in the medium |
| D. | All of the above |
| Answer» E. | |
| 44. |
The best described action of Pluronic F68 (non-ionic detergent) in a cell culture medium is that, it |
| A. | acts on the surface properties of the cells and the culture medium |
| B. | provides nutrients for the cells |
| C. | acts as a flocculant |
| D. | acts as a coagulant |
| Answer» B. provides nutrients for the cells | |
| 45. |
The Komologorov eddy size |
| A. | is constant at all stirrer speeds |
| B. | increases with stirrer speed |
| C. | decreases with stirrer speed |
| D. | becomes zero when the stirrer speed is very low |
| Answer» D. becomes zero when the stirrer speed is very low | |
| 46. |
Reynolds number for laminar flow over a plate should be less than |
| A. | 500 mm |
| B. | 5 x 10⁵ |
| C. | 5 x 10⁵ |
| D. | 5 m |
| Answer» D. 5 m | |
| 47. |
The approach which is commonly used to determine the level of damage to animal cells in a culture medium is to monitor |
| A. | the concentration of lactate in the medium |
| B. | the level of lactate oxidase activity in the medium |
| C. | the level of lactate dehydrogenase activity |
| D. | the level of lactase activity in the medium |
| Answer» D. the level of lactase activity in the medium | |
| 48. |
A Brookfield viscometer cannot determine the shear stress because |
| A. | the shear stress is not defined |
| B. | a computer is required |
| C. | the impeller type is given only by numbers |
| D. | all of the above |
| Answer» B. a computer is required | |
| 49. |
Which pattern of mixing is preferred in stirred tank reactors during the culture of aerobic microorganisms? |
| A. | Laminar flow |
| B. | Transient flow |
| C. | turbulent flow |
| D. | all of these |
| Answer» D. all of these | |
| 50. |
The viscosity of the culture fluid is classified as both pseudoplastic and thixotropic which indicates that the viscosity |
| A. | increases with stirring speed but decreases with mixing time |
| B. | increases with stirring speed and increases with mixing time |
| C. | decreases with stirring speed but increases with mixing time |
| D. | decreases with stirring speed and decreases with mixing time |
| Answer» E. | |