McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 451. |
Dehydration is the process of removal of |
| A. | hydrogen from water |
| B. | hydrogen from hydrocarbon |
| C. | moisture from anything that is wet |
| D. | hydrogen from alcohols |
| E. | addition of water vapour to a substance |
| Answer» C. moisture from anything that is wet | |
| 452. |
For minimum work in multistage compression, the work done on |
| A. | First stage should be least |
| B. | Last stage should be least |
| C. | All stage should be equal |
| D. | There is no such consideration |
| E. | None of the above |
| Answer» C. All stage should be equal | |
| 453. |
For the same maximum pressure and heat input the least efficient cycle is |
| A. | Diesel cycle |
| C. | Otto cycle |
| D. | Weight of engine |
| E. | Brayton |
| Answer» C. Otto cycle | |
| 454. |
A Curtis turbine is |
| A. | A velocity compounded readtion turbine |
| B. | A pressure compounded reaction turbine |
| C. | A pure reaction turbine |
| D. | An impulse reaction turbine |
| E. | None of the above |
| Answer» A. A velocity compounded readtion turbine | |
| 455. |
If the performance of diesel engines of different sizes, cylinder dimensions and horse power ratings are to be compared, which of the following parameter can be used for such comparison? |
| A. | Air-fuel ratio |
| B. | Brake specific fuel consumption |
| C. | Volumetric efficiency |
| D. | Swept volume |
| E. | None of the above |
| Answer» B. Brake specific fuel consumption | |
| 456. |
For same heat input and same compression ratio |
| A. | Otto cycle and Diesel cycle are equally efficient |
| B. | Otto cycle is less efficient than Diesel cycle |
| C. | Otto cycle is more efficient than Diesel cycle |
| D. | Efficiency depends mainly on working substance |
| E. | None of the above |
| Answer» C. Otto cycle is more efficient than Diesel cycle | |
| 457. |
The volumetric efficiency of a well adjusted engine at full load may be |
| A. | 40 to 55 percent |
| B. | 10 to 30 percent |
| C. | 75 to 95 percent |
| D. | 50 to 65 percent |
| E. | 30 to 45 percent |
| Answer» C. 75 to 95 percent | |
| 458. |
In Ambassador car, the engine is |
| A. | Multi-cylinder type |
| B. | V-type |
| C. | Air cooled and reciprocating engines |
| D. | Horizontal |
| E. | Constant speed type |
| Answer» A. Multi-cylinder type | |
| 459. |
Dehydration means |
| A. | Removing hydrogen from a mixture |
| B. | Removing hydrogen from a hydrocarbon |
| C. | Removing water from any matter |
| D. | Removing hydrides from any matter |
| E. | Any of the above |
| Answer» C. Removing water from any matter | |
| 460. |
Absolute pressure is |
| A. | Gauge pressure |
| B. | Gauge pressure + 1.03 kg/cm2 |
| C. | Gauge pressure-atmospheric pressure |
| D. | Gauge pressure + atmospheric pressure |
| E. | None of the above |
| Answer» D. Gauge pressure + atmospheric pressure | |
| 461. |
Samples of exhaust gases from following engines have been collected |
| A. | Diesel engine |
| B. | Gas engine |
| C. | 600;1 |
| D. | Petrol engine |
| E. | Jet propulsion unit |
| Answer» E. Jet propulsion unit | |
| 462. |
Normally the colour of exhaust from a petrol engine is |
| A. | Reddish |
| B. | Black |
| C. | Yellowish |
| D. | Bluish |
| E. | Violet |
| Answer» D. Bluish | |
| 463. |
The boilers using lignite as fuel do not use |
| A. | Horizontal burner, pulverized fuel |
| B. | Travelling grate stoker |
| C. | U-flame pulverized fuel burner |
| D. | Speader stoker |
| E. | Underfeed stoker |
| Answer» E. Underfeed stoker | |
| 464. |
Cetane number of diesel generally used in India is in the range |
| A. | 55 to 65 |
| B. | 40 to 55 |
| C. | 20 to 25 |
| D. | 15 to 20 |
| E. | 10 to 15 |
| Answer» B. 40 to 55 | |
| 465. |
Scavenging efficiency of a four stroke diesel engine is |
| A. | In the range 80 to 95 percent |
| B. | In the range 50 - 80 percent |
| C. | Below 50 percent |
| D. | Between 100% and 95% |
| E. | None of the above |
| Answer» D. Between 100% and 95% | |
| 466. |
The bottom ring on the piston is known as |
| A. | Oil ring |
| B. | Scrapper ring |
| C. | Compression ring |
| D. | Groove ring |
| E. | Any of the above |
| Answer» A. Oil ring | |
| 467. |
In a compression ignition engine squish is |
| A. | Created at the beginning of suction stroke |
| B. | Created at the end of suction stroke |
| C. | Created during combustion |
| D. | Created towards the end of compression stroke |
| E. | None of the above |
| Answer» D. Created towards the end of compression stroke | |
| 468. |
Which locomotives has the highest unbalanced forces? |
| A. | Electric locomotives |
| B. | Steam locomotives |
| C. | Carbon dioxide |
| D. | Diesel locomotives |
| Answer» B. Steam locomotives | |
| 469. |
For the same power and same speed, the flywheel of a two stroke engine as compared to that of a four stroke engine will be |
| A. | There is no correlation |
| B. | Same size |
| C. | Small |
| D. | Bigger |
| E. | Different shape |
| Answer» D. Bigger | |
| 470. |
The maximum amount of dissociation occurs in the burnt gases of a |
| A. | Carbon dioxide |
| B. | lean mixture |
| C. | chernically correct mixture |
| D. | rich fuel mixture |
| E. | weak fuel mixture |
| Answer» C. chernically correct mixture | |
| 471. |
In a Carnot cycle the algebraic sum of the entropy changes for the cycle is |
| A. | Zero |
| B. | Either positive or negative |
| C. | Negative |
| D. | Depends on the properties of working substance |
| E. | Positive |
| Answer» A. Zero | |
| 472. |
Blue smoke from a diesel engine indicates the presence of |
| A. | Unburnt carbon |
| B. | Unburnt oil |
| C. | Carbon dioxide |
| D. | Carbon monoxide |
| E. | Nitrous oxide |
| Answer» B. Unburnt oil | |
| 473. |
A turbo-charger is used |
| A. | In gas turbines for compression of air |
| B. | For supercharging reciprocating engine |
| C. | In jet propulsion units |
| D. | In rockets for producing air fuel mixture |
| E. | None of the above |
| Answer» B. For supercharging reciprocating engine | |
| 474. |
For same compression ratio and same heat input |
| A. | Otto cycle is more efficient |
| B. | Diesel cycle is more efficient |
| C. | Both are equally efficient |
| E. | None of the above |
| Answer» A. Otto cycle is more efficient | |
| 475. |
Which is the external loss in a steam turbine? |
| A. | Blade friction losses |
| B. | Nozzle losses |
| C. | Disc friction losses |
| D. | Back pressure losses |
| E. | Gland leakage losses |
| Answer» D. Back pressure losses | |
| 476. |
If engines of different horse power, rpm, cylinder dimensions are to be compared for their performance, the parameter of comparison could be |
| A. | Mean effective pressure |
| B. | Specific speed |
| C. | Exhaust temperature |
| D. | Fuel consumption |
| E. | Unit speed |
| Answer» A. Mean effective pressure | |
| 477. |
Ambassador car engine is |
| A. | F-type |
| B. | Overhead valve type |
| C. | Side valve type |
| D. | L-type |
| E. | Overhead inlet and side exhaust type |
| Answer» B. Overhead valve type | |
| 478. |
Which of the following chemical acts as anti-freeze? |
| A. | Naphtha |
| B. | Glycol |
| C. | Ethyl alcohol |
| D. | Lead acetate |
| E. | n-heptane |
| Answer» B. Glycol | |
| 479. |
A low pressure accumulator is generally used with which of the following turbine |
| A. | Mixed pressure turbine |
| B. | Back pressure turbine |
| C. | Impulse turbine |
| D. | Condensing turbine |
| E. | Reaction turbine |
| Answer» A. Mixed pressure turbine | |
| 480. |
Which is not the cause for loss of heat in boiler due to incomplete combustion? |
| A. | Under cooling of furnace at low ratings |
| B. | Improper secting of boiler |
| C. | Insufficient air supply |
| D. | Boiler drum uninsulated |
| E. | Fuel bend in proof condition |
| Answer» D. Boiler drum uninsulated | |
| 481. |
Temporary hardness of water is caused by |
| A. | Bicarbonates of calcium and magnesium |
| B. | Sulphates of calcium and magnesium |
| C. | Chlorides of calcium and magnesium |
| D. | Nitrates of calcium and magnesium |
| E. | None of the above |
| Answer» A. Bicarbonates of calcium and magnesium | |
| 482. |
Crankcase explosion occurs in |
| A. | Four stroke SI engines |
| B. | Four stroke Cl engines |
| C. | Two stroke Cl engines |
| D. | Gas engines |
| E. | Two stroke SI engines |
| Answer» E. Two stroke SI engines | |
| 483. |
Which of the following offers best resistance to knocking in S.I. engines? |
| A. | Aromatics |
| B. | Paraffins |
| C. | Carbon dioxide |
| D. | Naphthenes |
| E. | Olefins |
| Answer» A. Aromatics | |
| 484. |
Which of the following engine can work on very lean mixture? |
| A. | Petrol engine |
| B. | Diesel engine |
| C. | Two stroke engine |
| D. | Wankel engine |
| E. | Four stroke engine |
| Answer» B. Diesel engine | |
| 485. |
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» C. Product of boiler efficiency, turbine efficiency and generator efficiency | |
| 486. |
In gas and petrol engines thermal efficiency may be expected in the range |
| A. | 50 percent |
| B. | 30 to 35 percent |
| C. | 10 - 15 percent |
| D. | 15 to 25 percent |
| E. | 60 percent |
| Answer» B. 30 to 35 percent | |
| 487. |
A 200 MW generator should be cooled by |
| A. | Nitrogen |
| B. | Hydrogen peroxide |
| C. | Hydrogen |
| D. | Water |
| E. | Air |
| Answer» C. Hydrogen | |
| 488. |
Which of the following exists as highest pressure in a diesel engine |
| A. | Exhaust gases in silencer |
| B. | Lubricating oil |
| C. | Fuel at the time of injection |
| D. | Air at the end of compression stroke |
| E. | Air during suction |
| Answer» C. Fuel at the time of injection | |
| 489. |
A camshaft is not provided in case of |
| A. | Two stroke engines |
| B. | High speed engines |
| C. | Multicylinder engines |
| D. | ir cooled engines |
| E. | Vertical engines |
| Answer» A. Two stroke engines | |
| 490. |
The compression ratio in case of a gas turbine is of the order of |
| A. | 7 |
| B. | 12 |
| C. | 20 |
| D. | 5 |
| E. | 24 |
| Answer» A. 7 | |
| 491. |
Corona is generally accompanied by a faint glow and |
| A. | Spark |
| B. | Sparking |
| C. | Heating of conductors |
| D. | Explosion |
| E. | Hissing noise |
| Answer» E. Hissing noise | |
| 492. |
If after some use the lower part, electrodes and beathing space of a spark plug are found coated by deposits of soot and carbon, the conclusion will be |
| A. | Spark plug is of proper heat rating |
| B. | Spark advance is incorrect |
| C. | Spark plug is short circuited |
| D. | Composition of mixture in the engine is correct |
| E. | Spark plug is of too high heat rating |
| Answer» E. Spark plug is of too high heat rating | |
| 493. |
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» B. Decreases | |
| 494. |
A fan is being used under certain conditions. If the fan speed is doubled the power requirement will be |
| A. | 8 times |
| B. | 16 times |
| C. | Unchanged |
| D. | Double of the original |
| E. | Four times |
| Answer» A. 8 times | |
| 495. |
A jet engine has |
| A. | Propeller on top |
| B. | No propeller |
| C. | Propeller in back |
| D. | Two propellers |
| E. | Propeller in front |
| Answer» B. No propeller | |
| 496. |
In jet engines the compression ratio |
| A. | Varies with altitude |
| B. | Varies with square of speed |
| C. | Varies as cube of speed |
| D. | Remains constant |
| E. | None of the above |
| Answer» B. Varies with square of speed | |
| 497. |
Steam trap is a device that |
| A. | Allows passage of water but prevents the passage of steam |
| B. | Allows passage of air but prevents passage of steam |
| C. | Allows passage of the flue gases but prevents flow of steam |
| D. | None of the above |
| E. | Chain grate stokers |
| Answer» A. Allows passage of water but prevents the passage of steam | |
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