McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 251. |
The ratio of total useful heat drop to the total isentropic heat drop is called? |
| A. | rankine efficiency |
| B. | stage efficiency |
| C. | internal efficiency |
| D. | none of the mentioned |
| Answer» C. internal efficiency | |
| 252. |
What is the action of steam in a steam turbine? |
| A. | neither static nor dynamic |
| B. | dynamic |
| C. | static |
| D. | both dynamic & static |
| Answer» B. dynamic | |
| 253. |
The critical pressure gives the velocity of steam at the throat ___________ |
| A. | equal to the velocity of sound |
| B. | more than velocity of sound |
| C. | less than the velocity of light |
| D. | none of the mentioned |
| Answer» A. equal to the velocity of sound | |
| 254. |
The flow through a nozzle is regarded as ___________ |
| A. | isothermal flow |
| B. | isobaric flow |
| C. | isochoric flow |
| D. | isentropic flow |
| Answer» D. isentropic flow | |
| 255. |
The steam leaves the nozzle at a ____________ |
| A. | low pressure and a high velocity |
| B. | high pressure and a high velocity |
| C. | high pressure and a low velocity |
| D. | low pressure and a low velocity |
| Answer» A. low pressure and a high velocity | |
| 256. |
De-Laval turbine is a ____________ |
| A. | multi rotor impulse turbine |
| B. | impulse reaction turbine |
| C. | single rotor impulse turbine |
| D. | none of the mentioned |
| Answer» C. single rotor impulse turbine | |
| 257. |
The Parsons’ reaction turbine has ____________ |
| A. | only moving blades |
| B. | only fixed blades |
| C. | fixed and moving blades of different shape |
| D. | identical fixed and moving blades |
| Answer» D. identical fixed and moving blades | |
| 258. |
The ratio of the useful heat drop to the isentropic heat drop is called ____________ |
| A. | condenser efficiency |
| B. | nozzle efficiency |
| C. | vacuum efficiency |
| D. | boiler efficiency |
| Answer» B. nozzle efficiency | |
| 259. |
Rateau turbine is ____________ |
| A. | pressure-velocity compounded turbine |
| B. | simple reaction turbine |
| C. | velocity compounded turbine |
| D. | pressure compounded turbine |
| Answer» D. pressure compounded turbine | |
| 260. |
The value of the reheat factor varies from ____________ |
| A. | 1.08 to 1.10 |
| B. | 1.2 to 1.6 |
| C. | 1.6 to 2 |
| D. | 1.02 to 1.06 |
| Answer» D. 1.02 to 1.06 | |
| 261. |
In reaction turbines, the axial thrust is due to ____________ |
| A. | pressure drop across the rotor |
| B. | change in axial velocity |
| C. | both pressure drop across the rotor and change in axial velocity |
| D. | none of the mentioned |
| Answer» C. both pressure drop across the rotor and change in axial velocity | |
| 262. |
The flow of steam is super-sonic ____________ |
| A. | in the convergent portion of the nozzle |
| B. | at the entrance to the nozzle |
| C. | at the throat of the nozzle |
| D. | in the divergent portion of the nozzle |
| Answer» D. in the divergent portion of the nozzle | |
| 263. |
The variation of steam pressure in the nozzle depends upon ____________ |
| A. | dryness fraction of steam |
| B. | specific volume of steam |
| C. | velocity of steam |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 264. |
A binary vapour plant consists of ____________ |
| A. | mercury boiler |
| B. | steam turbine |
| C. | steam condenser |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 265. |
The steam enters the nozzle at a ____________ |
| A. | low pressure and a low velocity |
| B. | high pressure and a low velocity |
| C. | low pressure and a high velocity |
| D. | high pressure and a high velocity |
| Answer» D. high pressure and a high velocity | |
| 266. |
In a reaction turbine, when steam flows through the fixed blades ____________ |
| A. | pressure decreases while velocity increases |
| B. | pressure increases while velocity decreases |
| C. | pressure and velocity both increases |
| D. | pressure and velocity both decreases |
| Answer» A. pressure decreases while velocity increases | |
| 267. |
Steam turbines are used for ____________ |
| A. | electric power generation |
| B. | large marine propulsion |
| C. | direct drive of fans, compressors, pumps |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 268. |
Curtis turbine is a ____________ |
| A. | pressure compounded turbine |
| B. | velocity compounded turbine |
| C. | simple reaction turbine |
| D. | pressure-velocity compounded turbine |
| Answer» D. pressure-velocity compounded turbine | |
| 269. |
Which of the following statement is correct? |
| A. | the expansion of steam in a nozzle follows rankine cycle |
| B. | the friction in the nozzle increases the dryness fraction of steam |
| C. | the pressure of steam at throat is called critical pressure |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 270. |
What is the purpose of governing in steam turbines? |
| A. | reheat the steam and improve its quality |
| B. | maintain the speed of the turbine |
| C. | reduce the effective heat drop |
| D. | completely balance against end thrust |
| Answer» B. maintain the speed of the turbine | |
| 271. |
The ratio of the isentropic heat drop to the heat supplied is called ____________ |
| A. | stage efficiency |
| B. | reheat factor |
| C. | internal efficiency |
| D. | rankine efficiency |
| Answer» D. rankine efficiency | |
| 272. |
The reheat factor depends upon ____________ |
| A. | exit pressure |
| B. | turbine stage efficiency |
| C. | initial pressure and superheat |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 273. |
What is the critical pressure ratio for initially dry saturated steam? |
| A. | 0.546 |
| B. | 0.577 |
| C. | 0.586 |
| D. | 0.578 |
| Answer» B. 0.577 | |
| 274. |
In an impulse turbine, steam expands ____________ |
| A. | wholly in nozzle |
| B. | partly in the nozzle and partly in blades |
| C. | wholly in blades |
| D. | none of the mentioned |
| Answer» A. wholly in nozzle | |
| 275. |
A steam nozzle converts ____________ |
| A. | heat energy of steam into potential energy |
| B. | potential energy into heat energy of steam |
| C. | heat energy of steam into kinetic energy |
| D. | kinetic energy into heat energy of steam |
| Answer» C. heat energy of steam into kinetic energy | |
| 276. |
If the critical pressure ratio for steam is 0.546, then the steam is initially ____________ |
| A. | wet |
| B. | dry saturated |
| C. | superheated |
| D. | none of the mentioned |
| Answer» C. superheated | |
| 277. |
A stage, in reaction turbine, is represented by ____________ |
| A. | each row of blades |
| B. | number of entries of steam |
| C. | number of exits of steam |
| D. | none of the mentioned |
| Answer» A. each row of blades | |
| 278. |
Steam turbines may be classified according to ____________ |
| A. | number of stages |
| B. | direction of steam flow |
| C. | mode of steam action |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 279. |
A steam nozzle converts ____________ |
| A. | heat energy of steam into kinetic energy |
| B. | kinetic energy of steam into heat energy |
| C. | potential energy into heat energy |
| D. | none of the mentioned |
| Answer» A. heat energy of steam into kinetic energy | |
| 280. |
A steam turbine with no nozzle is? |
| A. | reaction turbine |
| B. | impulse turbine |
| C. | reaction & impulse turbines |
| D. | none of the mentioned |
| Answer» A. reaction turbine | |
| 281. |
_______ of electricity in United States is produced using steam turbine. |
| A. | 88% |
| B. | 50% |
| C. | 100% |
| D. | 77% |
| Answer» A. 88% | |
| 282. |
When steam pressure ________ it becomes superficial fluid. |
| A. | decreases |
| B. | increases |
| C. | steam can not become superficial fluid |
| D. | none of the mentioned |
| Answer» B. increases | |
| 283. |
Steam turbines used in nuclear reactors use __________ |
| A. | superficial fluids |
| B. | high pressure steam |
| C. | specific heat |
| D. | none of the mentioned |
| Answer» A. superficial fluids | |
| 284. |
Superficial steam power plants operate at _____ temperatures. |
| A. | high |
| B. | low |
| C. | constant |
| D. | none of the mentioned |
| Answer» A. high | |
| 285. |
Energy efficiency of superficial steam is _________ |
| A. | low |
| B. | high |
| C. | same as other steams |
| D. | none of the mentioned |
| Answer» B. high | |
| 286. |
Superficial steam turbines can be operated at ________ |
| A. | medium speeds |
| B. | low speeds |
| C. | high speeds |
| D. | none of the mentioned |
| Answer» C. high speeds | |
| 287. |
Superficial steam turbines releases _______ CO2. |
| A. | high |
| B. | low |
| C. | does not release |
| D. | none of the mentioned |
| Answer» A. high | |
| 288. |
Which statement about reaction turbine is false? |
| A. | steam does not expand in nozzle |
| B. | blades acts like nozzles |
| C. | steam expands as flows over the rotor blades |
| D. | steam continuously losses its heat as flows over the rotor blades |
| Answer» D. steam continuously losses its heat as flows over the rotor blades | |
| 289. |
Reaction turbines are characterized by ___________ |
| A. | relatively low rpm and steam expension over nozzle |
| B. | relatively high rpm and steam expension over nozzle |
| C. | relatively low rpm and steam expension over rotor blades |
| D. | relatively high rpm and steam expansion over rotor blades |
| Answer» C. relatively low rpm and steam expension over rotor blades | |
| 290. |
In condensing turbine what is the back pressure of the turbine? |
| A. | very high |
| B. | above atmospheric pressure |
| C. | equal to atmospheric pressure |
| D. | below atmospheric pressure |
| Answer» D. below atmospheric pressure | |
| 291. |
Having two separate units for process heat and power is? |
| A. | useful |
| B. | useless |
| C. | pollution reducing |
| D. | none of the mentioned |
| Answer» B. useless | |
| 292. |
Back pressure turbine is placed between ____________ |
| A. | turbine & pump |
| B. | boiler & pump |
| C. | turbine & heat exchanger |
| D. | boiler & turbine |
| Answer» D. boiler & turbine | |
| 293. |
Addition of an infinitesimal amount of heat at the highest temperature is because ___________ |
| A. | to initiate reheating |
| B. | to initiate regeneration |
| C. | to initiate superheating |
| D. | none of the mentioned |
| Answer» C. to initiate superheating | |
| 294. |
High moisture content is involved during expansion of steam because ___________ |
| A. | to ensure uniform heating |
| B. | to ensure uniform cooling |
| C. | to obtain a higher temperature of heat addition |
| D. | to obtain a lower temperature of heat addition |
| Answer» C. to obtain a higher temperature of heat addition | |
| 295. |
What is the relation of the mean temperature of heat addition and cycle efficiency? |
| A. | both are inversely proportional |
| B. | both are directly proportional |
| C. | both are independent of each other |
| D. | none of the mentioned |
| Answer» B. both are directly proportional | |
| 296. |
Temperature of heat rejection in a condenser can be lowered by using? |
| A. | lubricant |
| B. | oil |
| C. | refrigerant |
| D. | diesel |
| Answer» C. refrigerant | |
| 297. |
The use of which of the following becomes necessary during expansion of steam? |
| A. | reheat |
| B. | regeneration |
| C. | refrigeration |
| D. | superheat |
| Answer» A. reheat | |
| 298. |
What is the specific heat of the ideal working fluid used in vapour power cycle? |
| A. | should be constant |
| B. | should be large |
| C. | should be small |
| D. | none of the mentioned |
| Answer» C. should be small | |
| 299. |
What is the importance of the freezing point of the working fluid in the vapour power cycle? |
| A. | freezing point of working fluid should be below the room temperature |
| B. | freezing point of working fluid should be above the room temperature |
| C. | freezing point of working fluid should be equal to the room temperature |
| D. | does not have any importance |
| Answer» A. freezing point of working fluid should be below the room temperature | |
| 300. |
The engines which are operating on gas power cycle are? |
| A. | cyclic |
| B. | non-cyclic |
| C. | either cyclic or non-cyclic |
| D. | none of the mentioned |
| Answer» C. either cyclic or non-cyclic | |
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