MCQOPTIONS
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MCQOPTIONS
This section includes 15 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
When the nozzle operates with the maximum mass flow, the nozzle is said to be |
| A. | underdamping |
| B. | overdamping |
| C. | choked |
| D. | none of these |
| Answer» D. none of these | |
| 2. |
The effect of supersaturation is that the |
| A. | exit velocity of steam reduces |
| B. | entropy and specific volume of the steam increases |
| C. | mass of the steam discharged increases |
| D. | all of these |
| Answer» E. | |
| 3. |
In an impulse turbine |
| A. | the steam is expanded in nozzles only and there is a pressure drop and heat drop |
| B. | the pressure and temperature of steam remains constant |
| C. | the steam is expanded both in fixed and moving blades continuously |
| D. | the steam is expanded in moving blades only |
| Answer» B. the pressure and temperature of steam remains constant | |
| 4. |
De-Laval turbines are mostly used |
| A. | where low speeds are required |
| B. | for small power purposes and low speeds |
| C. | for large power purposes |
| D. | for small power purposes and high speeds |
| Answer» E. | |
| 5. |
The effect of friction on the flow of steam through a nozzle is to |
| A. | increase the mass flow rate and to increase the exit temperature |
| B. | decrease the mass flow rate and to increase the wetness of steam |
| C. | decrease the mass flow rate and to decrease the wetness of steam |
| D. | increase the exit temperature without any effect on mass flow rate |
| Answer» D. increase the exit temperature without any effect on mass flow rate | |
| 6. |
Stage efficiency is also known as |
| A. | nozzle efficiency |
| B. | gross efficiency |
| C. | diagram efficiency |
| D. | none of these |
| Answer» C. diagram efficiency | |
| 7. |
In an ideal impulse turbine, the |
| A. | relative velocity at the inlet of the moving blade is equal to that at the outlet |
| B. | absolute velocity at the inlet of moving blade is equal to that at the outlet |
| C. | axial velocity at inlet is equal to that at the outlet |
| D. | whirl velocity at inlet is equalto that at the outlet |
| Answer» B. absolute velocity at the inlet of moving blade is equal to that at the outlet | |
| 8. |
In a nozzle, the effect of supersaturation is to |
| A. | decrease specific volume of steam |
| B. | decrease dryness fraction of steam |
| C. | increase the entropy |
| D. | increase the heat drop |
| Answer» D. increase the heat drop | |
| 9. |
The process of maintaining the speed of the turbine constant for various load conditions, is known as |
| A. | reheating |
| B. | bleeding |
| C. | none of these |
| D. | governing |
| Answer» E. | |
| 10. |
Which of the following statement is correct for steam turbines as compared to reciprocating steam engines? |
| A. | all of these |
| B. | A steam turbine develops higher speeds |
| C. | The steam consumption is less |
| D. | The efficiency of steam turbine is higher |
| Answer» B. A steam turbine develops higher speeds | |
| 11. |
The compounding of turbines is done in order to |
| A. | reduce speed of rotor |
| B. | reduce exit losses |
| C. | improve efficiency |
| D. | all of these |
| Answer» E. | |
| 12. |
The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called |
| A. | stage efficiency |
| B. | nozzle efficiency |
| C. | mechanical efficiency |
| D. | blading efficiency |
| Answer» B. nozzle efficiency | |
| 13. |
The density of supersaturated steam is about __________ that of the ordinary saturated vapour at the corresponding pressure. |
| A. | 2 times |
| B. | 8 times |
| C. | same as |
| D. | 4 times |
| Answer» C. same as | |
| 14. |
A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be |
| A. | 79 m/s |
| B. | 450 m/s |
| C. | 900 m/s |
| D. | 188 m/s |
| Answer» C. 900 m/s | |
| 15. |
The impulse turbine rotor efficiency will have a maximum value of 0.5 cos2 ?, where ? is the nozzle exit flow angle, if the |
| A. | blade velocity coefficient is unity |
| B. | blades are equiangular and frictionless |
| C. | blades are equiangular |
| D. | blade solidity is 0.65 |
| Answer» C. blades are equiangular | |