MCQOPTIONS
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MCQOPTIONS
This section includes 27 Mcqs, each offering curated multiple-choice questions to sharpen your Steam Nozzles and Turbines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The difference of supersaturated temperature and saturation temperature at that pressure is known as ....... |
| A. | Degree of supersaturation |
| B. | Degree of superheat |
| C. | Degree of undercooling |
| D. | None of these |
| Answer» D. None of these | |
| 2. |
For a convergent divergent nozzle,critical pressure ratio occurs when ...... |
| A. | Velocity at exit becomes sonic |
| B. | Shock wave of occurs |
| C. | Nozzle efficiency is maximum |
| D. | Increase in exit and inlet pressure ratio does not increase steam flow rate |
| Answer» E. | |
| 3. |
The superposition of steam results in slight...... |
| A. | Increase in entropy |
| B. | Increase of final dryness fraction |
| C. | Increase of discharge |
| D. | All the above |
| Answer» E. | |
| 4. |
For critical pressure ratio, the discharge through a nozzle is....... |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Some value between maximum and minimum |
| Answer» B. Minimum | |
| 5. |
That density of super saturated steam is about.........that of the ordinary saturated vapour at the corresponding pressure |
| A. | Same as |
| B. | 2 times |
| C. | 4 times |
| D. | 8 times |
| Answer» E. | |
| 6. |
In a nozzle,the effect of supersaturation is to....... |
| A. | Decrease the dryness fraction of steam |
| B. | Decreases the specific volume of steam |
| C. | Increase the entropy |
| D. | Increase the enthalpy drop |
| Answer» D. Increase the enthalpy drop | |
| 7. |
The critical pressure ratio for initially superheated steam is.......as compared to initially dry saturated steam |
| A. | More |
| B. | Less |
| C. | Same |
| D. | None of the above |
| Answer» C. Same | |
| 8. |
A nozzle is said to be choked when ....... |
| A. | Flow-through it is zero |
| B. | Flow is attained at maximum value corresponding to critical exit pressure |
| C. | It is not possible to increase the flow by increasing inlet pressure |
| D. | It is discharging into atmosphere |
| Answer» C. It is not possible to increase the flow by increasing inlet pressure | |
| 9. |
The Effect of friction in a nozzle......dryness fraction of steam |
| A. | Increases |
| B. | Decreases |
| C. | Same |
| D. | None of the above |
| Answer» B. Decreases | |
| 10. |
If a flow is to be continuously accelerated from a subsonic to a supersonic velocity in nozzle,it must ...... |
| A. | Be convergent |
| B. | Be divergent |
| C. | Have throat |
| D. | Have first divergent section and then convergent section |
| Answer» D. Have first divergent section and then convergent section | |
| 11. |
For a convergent divergent nozzle, the mass flow rate remains constant if the ratio of exit and inlet pressures......... |
| A. | Is less then critical pressure ratio |
| B. | Is equal to the critical pressure ratio |
| C. | Is more then critical pressure ratio |
| D. | Is infinity |
| Answer» D. Is infinity | |
| 12. |
Mack number is more than unity in the following portion of a convergent divergent nozzle...... |
| A. | Convergent potion |
| B. | Straight portion |
| C. | Throat |
| D. | Divergent potion |
| Answer» E. | |
| 13. |
Under thermal equilibrium, flow of steam is....... |
| A. | Isentropic |
| B. | Adiabatic |
| C. | Hyperbolic |
| D. | Polytropic |
| Answer» C. Hyperbolic | |
| 14. |
The effect of friction in nozzle is to ....... |
| A. | Keep dryness fraction constant |
| B. | Increase dryness fraction |
| C. | Decrease dryness fraction |
| D. | First increase dryness fraction upto certain limit and then decrees it |
| Answer» C. Decrease dryness fraction | |
| 15. |
Which of the following devices uses wilson's line in determining flow through it....... |
| A. | Steam engine |
| B. | |
| C. | C. |
| D. | D. |
| Answer» C. C. | |
| 16. |
The maximum velocity attainable at the throat of a steam nozzle is...... |
| A. | Much less than sonic velocity |
| B. | Slightly less then sonic velocity |
| C. | Sonic velocity |
| D. | Slightly more than sonic velocity |
| Answer» D. Slightly more than sonic velocity | |
| 17. |
The flow of steam is supersonic......... |
| A. | At the entrance to the nozzle |
| B. | At the throat of the nozzle |
| C. | In the convergent portion of the nozzle |
| D. | In the divergent portion of the nozzle |
| Answer» E. | |
| 18. |
The value of critical pressure ratio for initially wet steam is....... |
| A. | 0.546 |
| B. | 0.5 |
| C. | 0.554 |
| D. | 0.582 |
| Answer» E. | |
| 19. |
The value of critical pressure ratio for superheated steam is....... |
| A. | 0.5 |
| B. | 0.546 |
| C. | 0.454 |
| D. | 0.64 |
| Answer» C. 0.454 | |
| 20. |
The flow of steam in a nozzle is subsonic at...... |
| A. | Throat |
| B. | Entrance |
| C. | Convergent portion |
| D. | Divergent portion |
| Answer» D. Divergent portion | |
| 21. |
In convergent nozzle velocity velocity attained is....... |
| A. | Velocity of sound |
| B. | Supersonic velocity |
| C. | Around 500 m/sec |
| D. | 1000 meter/sec |
| Answer» E. | |
| 22. |
The steam leaves the nozzle at a......... |
| A. | High pressure and low velocity |
| B. | High-pressure and high velocity |
| C. | Low pressure and low velocity |
| D. | Low pressure and high velocity |
| Answer» E. | |
| 23. |
Shock effect in a nozzle is felt in......... |
| A. | Divergent portion |
| B. | Straight portion |
| C. | Convergent portion |
| D. | Throat |
| Answer» B. Straight portion | |
| 24. |
Nozzle efficiency is described as....... |
| A. | Isentropic heat drop/useful heat drop |
| B. | useful heat drop/isentropic heat drop |
| C. | saturation temperature/supersaturation temperature |
| D. | supersaturation temperature/saturation temperature |
| Answer» C. saturation temperature/supersaturation temperature | |
| 25. |
The critical pressure ratio for initially dry saturated steam is....... |
| A. | 0.528 |
| B. | 0.546 |
| C. | 0.577 |
| D. | 0.582 |
| Answer» D. 0.582 | |
| 26. |
The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 , where is the nozzle exit flow angle, if the |
| A. | blades are equiangular |
| B. | blade velocity coefficient is unity |
| C. | blades are equiangular and frictionless |
| D. | blade solidity is 0.65 |
| Answer» D. blade solidity is 0.65 | |
| 27. |
The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine |
| A. | same |
| B. | less |
| C. | more |
| Answer» C. more | |