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MCQOPTIONS
This section includes 1092 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
With increase in pressure |
| A. | enthalpy of dry saturated steam increases |
| B. | enthalpy of dry saturated steam decreases |
| C. | enthalpy of dry saturated steam remains same |
| D. | enthalpy of dry saturated steam first increases & thendecreases |
| Answer» C. enthalpy of dry saturated steam remains same | |
| 352. |
A Rankine cycle is lessefficient than Carnot cycle because |
| A. | the working fluid is steam |
| B. | heat is not added athighest temperature of cycle |
| C. | condensation processis extended into liquid phase |
| D. | superheating occurs at constant pressure |
| Answer» C. condensation processis extended into liquid phase | |
| 353. |
The unit of energy in SI units is |
| A. | joule (j) |
| B. | joule metre (jm) |
| C. | watt (w) |
| D. | joule/metre (j/m) |
| Answer» B. joule metre (jm) | |
| 354. |
Due to which of the following reasons the Carnot cycle cannot be realised in actual practice? |
| A. | high volume ratios in the cylinder |
| B. | very high pressure developed in the cylinder |
| C. | both a & b |
| D. | none of the above |
| Answer» D. none of the above | |
| 355. |
The flow through turbine on a Mollier chart isrepresented by |
| A. | vertical line |
| B. | horizontal line |
| C. | curved line convex up |
| D. | curved line convex down |
| Answer» B. horizontal line | |
| 356. |
When the temperature of a liquid is less than the saturation temperature at the given pressure, the liquid is called compressed liquid. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 357. |
Processes inside a thermal energy reservoir are quasi-static. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 358. |
During a polytropic expansion workobtained is 1.8 times the heat transferred. If ?=1.4, n will be |
| A. | 1.2 |
| B. | 1.19 |
| C. | 1.178 |
| D. | 1.155 |
| Answer» E. | |
| 359. |
If all the variables of a stream areindependent of time it is said to be in |
| A. | steady flow |
| B. | unsteady flow |
| C. | uniform flow |
| D. | closed flow |
| Answer» B. unsteady flow | |
| 360. |
3 COMPRESSIBILITY CHART AND ITS USE |
| A. | 300.5 k |
| B. | 304.5 k |
| C. | 310 k d) 312.5 k |
| D. | view answer |
| Answer» C. 310 k d) 312.5 k | |
| 361. |
Steady flow process requires that |
| A. | conditions do not change with time at any point |
| B. | conditions are the same at adjacent points at anyinstant |
| C. | conditions change steadily with the time |
| D. | is constant |
| Answer» B. conditions are the same at adjacent points at anyinstant | |
| 362. |
Higher dryness fraction of steam at turbine exit in aRankine cycle |
| A. | will increase cycle efficiency |
| B. | will increase turbine work |
| C. | will protect turbine blading |
| D. | will reduce pump work |
| Answer» D. will reduce pump work | |
| 363. |
During a polytropic expansion 25% of heat is converted into work while temperature of gas rises by 30 K, the specific heat of gas at constant volume is |
| A. | 10% w |
| B. | 12 % w |
| C. | 15% w |
| D. | 20% w |
| Answer» C. 15% w | |
| 364. |
A definite area or space where some thermodynamic process takes place is known as |
| A. | thermodynamic system |
| B. | thermodynamic cycle |
| C. | thermodynamic process |
| D. | thermodynamic law |
| Answer» B. thermodynamic cycle | |
| 365. |
The area under the curve on temperature entropy diagram represents |
| A. | work done during the process |
| B. | heat exchanged during the process |
| C. | change in internal energy during the process |
| D. | change in entropy during the process |
| Answer» C. change in internal energy during the process | |
| 366. |
According to Trouton’s rule, the ratio of latent heat of vaporization to the boiling point at 1.013 bar is |
| A. | 77 kj/kgmol k |
| B. | 88 kj/kgmol k |
| C. | 99 kj/kgmol k |
| D. | 100 kj/kgmol k |
| Answer» C. 99 kj/kgmol k | |
| 367. |
The first law of thermodynamics for steady flow |
| A. | accounts for all energy entering & leaving a controlvolume |
| B. | is an energy balance for a specified mass of fluid |
| C. | is an expression of the conservation of linearmomentum |
| D. | is primarily concerned with heat transfer |
| Answer» B. is an energy balance for a specified mass of fluid | |
| 368. |
The relationship between pressure & volume is expressed as pv?=const. Selectwrong statement |
| A. | expansion with n=0 is a constant pressure process |
| B. | expansion with n=? is an adiabatic process |
| C. | expansion with n=? is not possible |
| D. | expansion at constant temperature has n=1 |
| Answer» D. expansion at constant temperature has n=1 | |
| 369. |
The change of entropy is considered to be……… when heat is absorbed by the gas |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | none of the above |
| Answer» B. negative | |
| 370. |
Average temp.at which heat is supplied isincreased in |
| A. | simple rankine cycle |
| B. | reheat rankine cycle |
| C. | regenerative rankine cycle |
| D. | modified rankine cycle |
| Answer» D. modified rankine cycle | |
| 371. |
Work done on a system is taken to be |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | varies according to situation |
| Answer» C. zero | |
| 372. |
A piston –cylinder device contains 0.06m3 of saturated water vapour at 350 kPa pressure. Determine the temperature and mass of the vapour inside the cylinder. |
| A. | 0.104 kg |
| B. | 0.124 kg |
| C. | 0.134 kg |
| D. | 0.114 kg |
| Answer» E. | |
| 373. |
The continual motion of a movable device in the complete absence of friction is known as |
| A. | pmm2 |
| B. | pmm3 |
| C. | pmm1 |
| D. | pmm0 |
| Answer» C. pmm1 | |
| 374. |
The amount of heat absorbed by asystem at lower temperature is |
| A. | coeff. of performance |
| B. | efficiency |
| C. | work supplied |
| D. | refrigerating effect |
| Answer» D. refrigerating effect | |
| 375. |
The fundamental unit of enthalpy is |
| A. | mlt ???? |
| B. | ml??t???? |
| C. | ml??t ???? |
| D. | ml??t ???? |
| Answer» D. ml??t ???? | |
| 376. |
Which of the following processes is essentially irreversible |
| A. | isothermal |
| B. | adiabatic |
| C. | isentropic |
| D. | thrittling |
| Answer» E. | |
| 377. |
An 80 litre vessel contains 4 kg of R-134a at a pressure of 160 kPa. Determine the quality. |
| A. | 0.127 |
| B. | 0.137 |
| C. | 0.147 |
| D. | 0.157 |
| Answer» E. | |
| 378. |
By reducing the condenser pressure in Rankine power plant |
| A. | heat supplied increases & work of cycle decreases |
| B. | work of cycle & moisture content of steam in l.p side ofturbine increase |
| C. | heat supplied & efficiency of cycle increase |
| D. | work of cycle increases but heat supplied decreases |
| Answer» C. heat supplied & efficiency of cycle increase | |
| 379. |
Energy is said to be degraded each time it flows through a finite temperature difference. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 380. |
Which of the following statements, regarding a property of system, iscorrect? |
| A. | it is path function |
| B. | it is a point function |
| C. | it is always of intensive type |
| D. | none of the above |
| Answer» C. it is always of intensive type | |
| 381. |
Which of the following is irreversible? |
| A. | stirring work |
| B. | friction work in moving devices |
| C. | current flowing through a wire |
| D. | all of the mentioned |
| Answer» E. | |
| 382. |
Internal energy of a perfect gas dependson |
| A. | temperature, specificheats & pressure |
| B. | temperature, specificheats & enthalpy |
| C. | temperature, specific heats& entropy |
| D. | temperature only |
| Answer» E. | |
| 383. |
With the increase in pressure |
| A. | boiling point of water increases & enthalpy of evaporation increases |
| B. | boiling point of water increases & enthalpy of evaporation decreases |
| C. | boiling point of water decreases & enthalpy of evaporation increases |
| Answer» C. boiling point of water decreases & enthalpy of evaporation increases | |
| 384. |
A steam power plant working on Rankine cycle produces steam in the boiler at a rate of 100 kg/s with enthalpy of 3280 kJ/kg from water whose total heat content is 420 kJ/kg. The plant has Rankine efficiency of 24.65 while pump requires 5 kJ/kg of work. The turbine generates power of |
| A. | 71 mw |
| B. | 71.5 mw |
| C. | 72 mw |
| D. | 72.5 mw |
| Answer» B. 71.5 mw | |
| 385. |
Thermodynamic equillibrium is completely defined by the specification of |
| A. | generalised displacements |
| B. | internal energy |
| C. | enthalpy |
| D. | all of the above |
| Answer» E. | |
| 386. |
A thermal energy reservoir is a large body of |
| A. | small heat capacity |
| B. | large heat capacity |
| C. | infinite heat capacity |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 387. |
Which of the following is a type of energy? |
| A. | high grade energy |
| B. | low grade energy |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 388. |
……… is a non-quasistatic process |
| A. | free expansion of gas |
| B. | expansion of gas in a cylinder under constantpressure |
| C. | rapid leakage of air from a bicycle tyre |
| D. | gradual compression of gas inside a piston-cylinderarrangement |
| Answer» B. expansion of gas in a cylinder under constantpressure | |
| 389. |
An isentropic process is always |
| A. | irreversible & adiabatic |
| B. | reversible & isothermal |
| C. | frictionless & irreversible |
| D. | reversible & adiabatic |
| Answer» E. | |
| 390. |
The equation of state of an ideal gas is a relationship between the variables: |
| A. | pressure & volume |
| B. | pressure & temperature |
| C. | pressure, volume & temperature |
| D. | none of the above |
| Answer» D. none of the above | |
| 391. |
In all irrevesible processes, the entropy ofthe system |
| A. | remains unaltered |
| B. | reduces to zero |
| C. | increases |
| D. | none of the above |
| Answer» D. none of the above | |
| 392. |
Entropy of mixture of two gases aftersudden mixing is |
| A. | greater than |
| B. | less than its inputtemperature |
| C. | same as sum of entropy ofindividual gases |
| D. | unpredictable |
| Answer» B. less than its inputtemperature | |
| 393. |
The entropy may be expressed as afunction of |
| A. | pressure & temperature |
| B. | temperature & volume |
| C. | heat & work |
| D. | all of the above |
| Answer» B. temperature & volume | |
| 394. |
The processes of a Carnot cycle are |
| A. | two adiabatic & two constant volume |
| B. | one constant volume &one constant pressure & two isentropies |
| C. | two adiabatics & two isothermals |
| D. | two isothermals & two isentropies |
| Answer» E. | |
| 395. |
Which of the following cycles is used in thermalpower plants? |
| A. | brayton |
| B. | carnot |
| C. | ericsson |
| D. | rankine |
| Answer» E. | |
| 396. |
When considering a finite energy source, its working fluid expands, |
| A. | reversibly |
| B. | adiabatically |
| C. | reversibly and adiabatically |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 397. |
The value of the univesal gas constant is |
| A. | 0.314 j/kg k |
| B. | 83.14 kj/kg k |
| C. | 848 kj/kg k |
| D. | 8.314 kj/kg k |
| Answer» E. | |
| 398. |
When gases which are at equal pressure and temperature are mixed adiabatically without work, then |
| A. | internal energy of the gaseous system remains constant |
| B. | heat transfer of the gaseous system remains constant |
| C. | entropy of the gaseous system remains constant |
| D. | all of the mentioned |
| Answer» B. heat transfer of the gaseous system remains constant | |
| 399. |
Joule's law states that the specific internal energy of a gas depends only on |
| A. | the pressure of the gas |
| B. | the volume of the gas |
| C. | the temperature of the gas |
| D. | none of the above |
| Answer» D. none of the above | |
| 400. |
A Rankine cycle with reheat |
| A. | increases heat supply but reduces work |
| B. | increases efficiency but reduces work |
| C. | increases moisture content in l.p side of turbine but increases work |
| D. | increases efficiency but reduces moisture content in l.p side of turbine |
| Answer» E. | |