MCQOPTIONS
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MCQOPTIONS
This section includes 460 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Engines knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
Turbidity in boiler feed water causes |
| A. | Sludge |
| B. | Embrittlement |
| C. | Corrosion |
| D. | Scale |
| E. | None of the above |
| Answer» B. Embrittlement | |
| 402. |
Flash point of a liquids is the temperature at which |
| A. | The fuel ignites with clearly visible flash |
| B. | Fuel vaporises at the prescribed rate |
| C. | The fuel emits vapours at a rate which produces an inflammable mixture with air |
| D. | The fuel ignites without a park |
| E. | The fuel spontaneously ignites |
| Answer» D. The fuel ignites without a park | |
| 403. |
The top ring nearest to the piston crown is known as |
| A. | Oil ring |
| B. | Scrapper ring |
| C. | Compression ring |
| D. | Groove ring |
| E. | Any of the above |
| Answer» D. Groove ring | |
| 404. |
A vacuum of 712 mm was obtained with the barometer reading 753 mm of mercury. The corrected vacuum to a standard barometer of 760 would be |
| A. | 719 mm Hg |
| B. | 753 mm Hg |
| C. | 706 mm Hg |
| D. | 760 mm Hg |
| E. | 712 mm Hg |
| Answer» B. 753 mm Hg | |
| 405. |
A diesel power plant is best suited as |
| A. | Base load plant |
| B. | Stand by plant |
| C. | Peak load plant |
| D. | General purpose plant |
| E. | None of the above |
| Answer» C. Peak load plant | |
| 406. |
Which one of the following factors will not assist in improving thermal efficiency of a compression ignition engine? |
| A. | Fine atomisation and even distribution of fuel |
| B. | Minimum heat loss during combustion |
| C. | Clear exhaust |
| D. | High surface to volume ratio |
| E. | Any of the above |
| Answer» E. Any of the above | |
| 407. |
A mixture containing 60% cetane and 40% Iso-octane will have |
| A. | Cetane number 60 |
| B. | Cetane number 40 |
| C. | Octane number 60 |
| D. | Octane number 40 |
| E. | None of the above |
| Answer» F. | |
| 408. |
The air standard efficiency of a turbine cycle is 56.5%, which one of the following may be Carnot efficiency between the temperature limits of the cycle? |
| A. | 75% |
| B. | 64% |
| C. | 50% |
| D. | 100% |
| E. | 56.50% |
| Answer» C. 50% | |
| 409. |
A gas turbine cycle with regenerator has a thermal efficiency of 26%. If intercooler and reheater are also introduced what could be expected thermal efficiency |
| A. | 50% |
| B. | 10% |
| C. | 60% |
| D. | 40% |
| E. | 30% |
| Answer» F. | |
| 410. |
In a cut off covered steam engine |
| A. | Admission pressore remains constant while cut off is varied |
| B. | Admission pressure is reduced while cut off remains unaltered |
| C. | Admission pressure and cut off both are varied |
| D. | Neither admission pressure nor cut off is varied |
| E. | Admission pressure is increased while cut off remains unaltered |
| Answer» B. Admission pressure is reduced while cut off remains unaltered | |
| 411. |
In a four stage compressor system first and third stage pressures are 1 and 9 kg/cm2 respectively. What will be the fourth stage delivery pressure |
| A. | 243 kg/cm2 |
| B. | 81 kg/cm2 |
| C. | 3 kg/cm2 |
| D. | 27 kg/cm2 |
| E. | 9 kg/cm2 |
| Answer» C. 3 kg/cm2 | |
| 412. |
As the compression ratio increases the volumetric efficiency of air compressor |
| A. | Increases |
| B. | Decreases |
| C. | Does not change |
| D. | Unpredictable |
| E. | None of the above |
| Answer» C. Does not change | |
| 413. |
A gas turbine plant operates between 1 ata and 9 ata with minimum and maximum cycle temperature of 25?C and 1000?C. A two stage compressor is provided with perfect intercooling and work is equally divided between the two stages. The intermediate pressure will be |
| A. | 5.5 ata |
| B. | 3 ata |
| C. | 4 ata |
| D. | 7.5 ata |
| E. | 5 ata |
| Answer» C. 4 ata | |
| 414. |
The thermal efficiency of a dual cycle engine with fixed compression ratio and fixed quantity of het and with increase in pressure ratio, will |
| A. | Increase |
| B. | Decrease |
| C. | Not change |
| D. | Depends on another factors |
| E. | None of the above |
| Answer» B. Decrease | |
| 415. |
If the pressures at the beginning and end of compression in an Otto cycle engine are 1 kg/cm2 and 8 kg/cm2 respectively the air standard efficiency will be |
| A. | 45% |
| B. | 50% |
| C. | 57% |
| D. | 50% |
| E. | 40% |
| Answer» E. 40% | |
| 416. |
Overall thermal efficiency of a thermal power plant is |
| A. | Carnot cycle efficiency |
| B. | 50 to 70% of theoretical efficiency |
| C. | Product of boiler efficiency, turbine efficiency and generator efficiency |
| D. | Rankine cycle efficiency |
| E. | None of the above |
| Answer» D. Rankine cycle efficiency | |
| 417. |
A gas used in gas engine trial was tested in a Boys Calorimeter. The pressure of gas supply was 7 cm of water column. If the barometric pressure is 760 mm of mercury, the absolute pressure of the gas would be |
| A. | 0.007 kg/sq-cm |
| B. | 0.14 kg/sq-cm |
| C. | 1.04 kg/sq-cm |
| D. | 1.14 kg/sq-cm |
| E. | None of the above |
| Answer» D. 1.14 kg/sq-cm | |
| 418. |
A back pressure generally operates on pressures in the range |
| A. | 150 - 200 kg/cm2 |
| B. | 15 - 40 kg/cm2 |
| C. | 100 - 150 kg/cm2 |
| D. | 50 - 100 kg/cm2 |
| E. | 200 - 350 kg/cm2 |
| Answer» C. 100 - 150 kg/cm2 | |
| 419. |
Which one of the following acts as ignition accelerator for C.I. engines fuel |
| A. | Acetone peroxide |
| B. | Hydrogen peroxide |
| C. | None of above |
| D. | n heptane |
| E. | Armatic compounds |
| Answer» B. Hydrogen peroxide | |
| 420. |
Which of the following is not used as ignition accelerator for diesel engine fuel? |
| A. | Ethyl nitrate |
| B. | Methyl alcohol |
| C. | Acetone peroxise |
| D. | Isoamyl nitrate |
| E. | All of the above |
| Answer» C. Acetone peroxise | |
| 421. |
Which fuel will have least air consumption during combustion |
| A. | Spirit |
| B. | Benzol |
| C. | Diesel fuel oil |
| D. | Gasoline |
| E. | Lubricating oil |
| Answer» B. Benzol | |
| 422. |
Which of the following engine uses two fuel simultaneously? |
| A. | Multi-fuel engine |
| B. | Duel fuel engine |
| C. | Wankle engine |
| D. | Free piston gas generator |
| E. | All of the above |
| Answer» C. Wankle engine | |
| 423. |
In order to achieve maximum possible fuel economy the design features which will be affected are |
| A. | Volumetric efficiency |
| B. | Compression ratio |
| C. | Method of charging |
| D. | Atomization |
| E. | None of the above |
| Answer» E. None of the above | |
| 424. |
Which of the following fuel can be obtained by fermentation of vegetable matter? |
| A. | Alcohol |
| B. | Gasoline |
| C. | Benzene |
| D. | Carbon dioxide |
| E. | Diesel |
| Answer» B. Gasoline | |
| 425. |
Which of the following will not be seen in a boiler using pulverised fuel? |
| A. | Chain in great stoker |
| B. | Feed pump |
| C. | Economiser |
| D. | Superheater |
| E. | Chimney |
| Answer» B. Feed pump | |
| 426. |
To augment the thrust of jet propulsion units part of the fuel is burned in the exhaust. How does this fuel burn |
| A. | Some chemicals rich in oxygen are mixed with fuel |
| B. | Oxygen is also supplied along with fuel |
| C. | 600;1 |
| D. | Fuel is never burned in exhaust pipe |
| E. | Fuel finds oxygen from excess air supplied to engine |
| Answer» F. | |
| 427. |
For steam engine having a throttle governor, a straight line is obtained when the total weight of steam used per hour is plotted against the indicated horse power. This line is known as |
| A. | Willian's line |
| B. | Clapeyron's line |
| C. | Bunsen line |
| D. | Calender's line |
| E. | Hopson's line |
| Answer» B. Clapeyron's line | |
| 428. |
Which of the following is a part of reciprocating steam engine and not a part of steam turbine plant? |
| A. | Condenser |
| B. | Governor |
| C. | Pressure gauge |
| D. | Cross head |
| E. | All of the above |
| Answer» E. All of the above | |
| 429. |
A steam turbine in which a part of the steam turbine after partial expansion is used for process heating and the remaining steam is further expanded for power generation, is known as |
| A. | Impulse turbine |
| B. | Regenerative turbine |
| C. | Back pressure turbine |
| D. | Pass out turbine |
| E. | 50% reaction turbine |
| Answer» E. 50% reaction turbine | |
| 430. |
The pressure of steam generated in a boiler as recorded by the Bourdon pressure gauge was 2.2 kg/sq-cm. If the barometer reads 774 mm of mercury the absolute pressure of steam would be |
| A. | 0.2 kg/sq-cm |
| B. | 9.774 kg/sq-cm |
| C. | 1.025 kg/sq-cm |
| D. | 77.4 mm of Hg |
| E. | 3.2526 kg/sq-cm |
| Answer» F. | |
| 431. |
In a throttle governed single cylinder steam engine 5 I.H.P. is developed when steam consumption is 50 kg per hour and 2 I.H.P. is developed when the steam consumption is 26 kg per hour. The steam consumptions when the engine develops 4 I.H.P. will be |
| A. | 46 |
| B. | 42 kg |
| C. | 40 kg |
| D. | 38 kg |
| E. | 37 kg |
| Answer» C. 40 kg | |
| 432. |
Regenerative feed heating of steam turbines is done primarily to |
| A. | Improve thermal efficiency of the condenser |
| B. | Increase the expansion range for steam in the turbine |
| C. | Improve overall efficiency of the plant |
| D. | Reduce pressure of steam in exhaust |
| E. | Reduce boiler losses in the gases |
| Answer» D. Reduce pressure of steam in exhaust | |
| 433. |
Reheating of steam for steam turbine cycle is done primarily to |
| A. | Reduce dryness fraction of exhaust steam |
| B. | Increase the pressure of steam in the condenser |
| C. | Increase boiler chimney draught |
| D. | Improve thermal efficiency of the plant |
| E. | All of the above |
| Answer» E. All of the above | |
| 434. |
The main purpose of compounding in case of steam turbines is to |
| A. | Reduced speed of rotor |
| B. | Reduced exist losses |
| C. | Improve thermal efficiency |
| D. | All of the above |
| E. | None of the above |
| Answer» E. None of the above | |
| 435. |
The value of reheat factor in case of steam turbines is usually |
| A. | 1.25 to 1.50 |
| B. | 1.02 to 1.06 |
| C. | 1.10 to 1.16 |
| D. | 1.75 to 2.50 |
| E. | 0.9 to 0.99 |
| Answer» C. 1.10 to 1.16 | |
| 436. |
Excessive moisture in steam in a steam turbine is likely to result in |
| A. | Erosion of turbine blades |
| B. | Excess work done by rotor due to momentum of water particles |
| C. | Overheating of turbine blaces |
| D. | Reduced load on condenser |
| E. | Reduced size of steam turbine |
| Answer» B. Excess work done by rotor due to momentum of water particles | |
| 437. |
Which of the following automobile is relatively free from pollution problems |
| A. | Diesel engine powered |
| B. | Wankel engine powered |
| C. | Batterly powered |
| D. | Gas turbine powered |
| E. | Petrol engine powered |
| Answer» D. Gas turbine powered | |
| 438. |
The chemical usually added for increasing the knock resistance of a petrol engine is |
| A. | Tetra-ethy lead |
| B. | n-heptane |
| C. | Pyro gallic acid |
| D. | Methyl alcohol |
| E. | Benzol |
| Answer» B. n-heptane | |
| 439. |
A hydrograph is a plot of discharge through a river versus |
| A. | Time |
| B. | Velocity of water |
| C. | Rate of flow of water |
| D. | None of the above |
| E. | None of the above |
| Answer» B. Velocity of water | |
| 440. |
Oil rings are slotted to |
| A. | Remove oil from cylinder |
| B. | Minimise friction |
| C. | Reduce the bulk |
| D. | Better lubrication of cylinder walls |
| E. | Provide an escape for the oil that the slot edges cut from the cylinder wall |
| Answer» F. | |
| 441. |
Thermionic converters are based on |
| A. | Seebeck effect |
| B. | Microwave theory |
| C. | Energy contained in thermal conductors |
| D. | Transfer of electrons |
| E. | None of the above |
| Answer» E. None of the above | |
| 442. |
In thermodynamic analysis, a pure substance is that which |
| A. | consists of only a single chemical species |
| B. | May have a number of chemical species that the composition remains constant |
| C. | has no dissolved impurities |
| D. | behaves as perfect gas |
| E. | None of the above |
| Answer» C. has no dissolved impurities | |
| 443. |
In a diesel engine the inlet pressure is more than the atmospheric pressure. Therefore; it can be concluded that |
| A. | The engine is high speed type |
| B. | The engine is air cooled |
| C. | The engine is water cooled |
| D. | The engine is slow speed type |
| E. | The engine is supercharged |
| Answer» F. | |
| 444. |
In compression ignition engine fuel ignition accelerators are added to |
| A. | Reduce combustion knock |
| B. | Accelerate combustion knock |
| C. | Reduce combustion chamber temp |
| D. | Increase delay period |
| E. | None of the above |
| Answer» B. Accelerate combustion knock | |
| 445. |
A diesel engine is to be redesigned to improve the overload capacity. The design feature which will be influenced is |
| A. | Size of fuel injection equipment |
| B. | Lubrication |
| C. | Air capacity of cylinder |
| D. | Cooling water velocity |
| E. | All of the above |
| Answer» F. | |
| 446. |
Octane number of petrol generally available is in the range |
| A. | 10 to 25 |
| B. | 55 to 65 |
| C. | 25 to 60 |
| D. | 20 to 75 |
| E. | 80 to 100 |
| Answer» F. | |
| 447. |
Working pressure of a boiler does not depend upon |
| A. | Factor of safety |
| B. | Tensile strength of shell |
| C. | Thickness of shell |
| D. | Efficiency of joint |
| E. | Type of fuel being fired |
| Answer» F. | |
| 448. |
In a impulse turbine while steam flows through the moving blades |
| A. | Velocity increases |
| B. | Velocity reduces |
| C. | Both velocity as well as pressure increase |
| D. | Velocity reduces while pressure increases |
| E. | Pressure reduces |
| Answer» C. Both velocity as well as pressure increase | |
| 449. |
Anthydrous substance is |
| A. | Dry substance |
| B. | Free of hydrogen |
| C. | Free of humidity |
| D. | Crystalline substance |
| E. | Free of water specially water of crystallization |
| Answer» F. | |
| 450. |
In spark ignition engines, the knocking tendency is reduced by |
| A. | Reduction of compression ratio |
| B. | Advancing ignition timing |
| C. | Increasing exhaust temperature |
| D. | Adding dope like tetra ethy lead to the fuel |
| E. | All of the above |
| Answer» E. All of the above | |