MCQOPTIONS
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MCQOPTIONS
This section includes 513 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. |
*/*_The air-fuel ratio of the petrol engine is controlled by? |
| A. | Fuel pump |
| B. | Governor |
| C. | Injector |
| D. | Carburettor |
| Answer» E. | |
| 352. |
%_In petrol engines, the delay period is of the order of_% |
| A. | 0.001 second |
| B. | 0.002 second |
| C. | 0.003 second |
| D. | 0.004 second |
| Answer» C. 0.003 second | |
| 353. |
%_The knocking tendency in compression ignition engines for a given fuel will be_% |
| A. | Enhanced by decreasing compression ratio |
| B. | Enhanced by increasing compression ratio |
| C. | Dependent on other factors |
| D. | None of the above |
| Answer» B. Enhanced by increasing compression ratio | |
| 354. |
%_The expansion of fuel in a four stroke cycle diesel engine_% |
| A. | Starts at 15° before top dead center and ends at 30° after top dead center |
| B. | Starts at top dead center and ends at 30° after top dead center |
| C. | Starts at 15° after top dead center and ends at 30° before bottom dead center |
| D. | May start and end anywhere |
| Answer» D. May start and end anywhere | |
| 355. |
_ The cetane (C‚ÇÅ‚ÇÜH‚ÇÉ‚ÇÑ) which is a straight chain paraffin, is assigned a cetane number of$? |
| A. | 0 |
| B. | 50 |
| C. | 100 |
| D. | 120 |
| Answer» D. 120 | |
| 356. |
_ The normal heptane (C‚ÇáH‚ÇÅ‚ÇÜ) is given a rating of ________ octane number.$? |
| A. | 0 |
| B. | 50 |
| C. | 100 |
| D. | 120 |
| Answer» B. 50 | |
| 357. |
_ The purpose of testing an internal combustion engine is$? |
| A. | To determine the information, which cannot be obtained by calculations |
| B. | To conform the data used in design, the validity of which may be doubtful |
| C. | To satisfy the customer regarding the performance of the engine |
| D. | All of the above |
| Answer» E. | |
| 358. |
_ Diesel as compared to petrol is$? |
| A. | Highly ignitable |
| B. | More difficult to ignite |
| C. | Less difficult to ignite |
| D. | None of these |
| Answer» C. Less difficult to ignite | |
| 359. |
_ A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.$? |
| A. | Half |
| B. | Same |
| C. | Double |
| D. | Four times |
| Answer» D. Four times | |
| 360. |
_ Polymerization is a chemical process in which molecules of a compound become$? |
| A. | Larger |
| B. | Slowed down |
| C. | Smaller |
| D. | Liquid |
| Answer» B. Slowed down | |
| 361. |
_ Which of the following does not relate to a spark ignition engine?$? |
| A. | Ignition coil |
| B. | Spark plug |
| C. | Carburettor |
| D. | Fuel injector |
| Answer» E. | |
| 362. |
_ Air fuel ratio for idling speed of a petrol engine is approximately$? |
| A. | 1 : 1 |
| B. | 5 : 1 |
| C. | 10 : 1 |
| D. | 15 : 1 |
| Answer» D. 15 : 1 | |
| 363. |
_ Number of working strokes per min. for a four stroke cycle engine are _________ the speed of the engine in r.p.m.$? |
| A. | Equal to |
| B. | One-half |
| C. | Twice |
| D. | Four-times |
| Answer» C. Twice | |
| 364. |
_ The size of inlet valve of an engine in comparison to exhaust valve is$? |
| A. | More |
| B. | Less |
| C. | Same |
| D. | More/less depending on capacity of engine |
| Answer» C. Same | |
| 365. |
_ The inlet valve of a four stroke cycle internal combustion engine remains open for$? |
| A. | 130° |
| B. | 180° |
| C. | 230° |
| D. | 270° |
| Answer» D. 270¬¨‚àû | |
| 366. |
_ In a four stroke cycle diesel engine, the compression$? |
| A. | Starts at 40° after bottom dead center and ends at 10° before top dead center |
| B. | Starts at 40° before top dead center and ends at 40° after top dead center |
| C. | Starts at top dead center and ends at 40° before bottom dead center |
| D. | May start and end anywhere |
| Answer» B. Starts at 40¬¨‚àû before top dead center and ends at 40¬¨‚àû after top dead center | |
| 367. |
_ The air-fuel ratio of the petrol engine is controlled by$? |
| A. | Fuel pump |
| B. | Governor |
| C. | Injector |
| D. | Carburettor |
| Answer» E. | |
| 368. |
_ In a four stroke cycle engine, the sequence of operations is$? |
| A. | Suction, compression, expansion and exhaust |
| B. | Suction, expansion, compression and exhaust |
| C. | Expansion, compression, suction and exhaust |
| D. | Compression, expansion, suction and exhaust |
| Answer» B. Suction, expansion, compression and exhaust | |
| 369. |
_ In petrol engine, using a fixed octane rating fuel and fixed compression ratio, supercharging will _________ the knocking tendency.$? |
| A. | Not effected |
| B. | Decrease |
| C. | Increase |
| D. | None of these |
| Answer» D. None of these | |
| 370. |
_ Compression loss in I.C engines occurs due to$? |
| A. | Leaking piston rings |
| B. | Use of thick head gasket |
| C. | Clogged air inlet slots |
| D. | All of the above |
| Answer» E. | |
| 371. |
_ The loud pulsating noise heard within the cylinder of an internal combustion engine is known as$? |
| A. | Detonation |
| B. | Turbulence |
| C. | Pre-ignition |
| D. | Supercharging |
| Answer» B. Turbulence | |
| 372. |
_ The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called$? |
| A. | Mechanical efficiency |
| B. | Overall efficiency |
| C. | Indicated thermal efficiency |
| D. | Volumetric efficiency |
| Answer» C. Indicated thermal efficiency | |
| 373. |
_ A diesel engine as compared to petrol engine (both running and rated load) is$? |
| A. | More efficient |
| B. | Less efficient |
| C. | Equally efficient |
| D. | Other factors will decide it |
| Answer» B. Less efficient | |
| 374. |
_ The injection pressure in a diesel engine is about$? |
| A. | 10 bar |
| B. | 100 bar |
| C. | 150 bar |
| D. | 500 bar |
| Answer» C. 150 bar | |
| 375. |
_ The spark ignition engines are governed by$? |
| A. | Hit and miss governing |
| B. | Qualitative governing |
| C. | Quantitative governing |
| D. | Combination of (B) and (C) |
| Answer» D. Combination of (B) and (C) | |
| 376. |
_ The probability of knocking in diesel engines is increased by$? |
| A. | High self ignition temperature |
| B. | Low volatility |
| C. | Higher viscosity |
| D. | All of these |
| Answer» E. | |
| 377. |
_ Pick up the wrong statement about supercharging$? |
| A. | Supercharging reduces knocking in diesel engines |
| B. | There can be limited supercharging in petrol engines because of detonation |
| C. | Supercharging at high altitudes is essential |
| D. | Supercharging results in fuel economy |
| Answer» E. | |
| 378. |
_ The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is$? |
| A. | Same |
| B. | Less |
| C. | More |
| D. | More or less depending on power rating |
| Answer» D. More or less depending on power rating | |
| 379. |
_ Thermal efficiency of a two stroke cycle engine is _________ a four stroke cycle engine.$? |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | None of these |
| Answer» C. Greater than | |
| 380. |
_ A 5 BHP engine running at full load would consume diesel of the order of$? |
| A. | 0.3 kg/hr |
| B. | 1 kg/hr |
| C. | 3 kg/hr |
| D. | 5 kg/hr |
| Answer» C. 3 kg/hr | |
| 381. |
_ For the same compression ratio$? |
| A. | Otto cycle is more efficient than the Diesel |
| B. | Diesel cycle is more efficient than Otto |
| C. | Both Otto and Diesel cycles are, equally efficient |
| D. | Compression ratio has nothing to do with efficiency |
| Answer» B. Diesel cycle is more efficient than Otto | |
| 382. |
_ The operation of forcing additional air under pressure into the engine cylinder is known as$? |
| A. | Supercharging |
| B. | Carburetion |
| C. | Turbulence |
| D. | Delay period |
| Answer» B. Carburetion | |
| 383. |
_ If the speed of the engine is increased, the indicated power will$? |
| A. | Increase |
| B. | Decrease |
| C. | Remain same |
| D. | None of these |
| Answer» B. Decrease | |
| 384. |
_ In a petrol engine, the fuel supplied to the engine cylinder is mixed with required quantity of air and the mixture is ignited with a$? |
| A. | Fuel pump |
| B. | Fuel injector |
| C. | Spark plug |
| D. | None of these |
| Answer» D. None of these | |
| 385. |
_ The object of providing masked inlet valve in the air passage of compression ignition engines is to$? |
| A. | Enhance flow rate |
| B. | Control air flow |
| C. | Induce primary swirl |
| D. | Induce secondary turbulence |
| Answer» D. Induce secondary turbulence | |
| 386. |
_ Morse test is used to determine the I.P. of a$? |
| A. | Single cylinder petrol engine |
| B. | Four stroke engine |
| C. | Single cylinder diesel engine |
| D. | Multi cylinder engine |
| Answer» E. | |
| 387. |
_ Pick up the false statement$? |
| A. | Thermal efficiency of diesel engine is about 34% |
| B. | Theoretically correct mixture of air and petrol is approximately 15:1 |
| C. | High speed compression engines operate on dual combustion cycle |
| D. | S.I. engines are quality governed engines |
| Answer» E. | |
| 388. |
_ In a typical medium speed 4-stroke cycle diesel engine the inlet valve$? |
| A. | Opens at 20° before top dead center and closes at 35° after the bottom dead center |
| B. | Opens at top dead center and closes at bottom dead center |
| C. | Opens at 10° after top dead center and closes 20° before the bottom dead center |
| D. | May open or close anywhere |
| Answer» B. Opens at top dead center and closes at bottom dead center | |
| 389. |
_ A diesel engine has compression ratio from$? |
| A. | 6 to 10 |
| B. | 10 to 15 |
| C. | 15 to 25 |
| D. | 25 to 40 |
| Answer» D. 25 to 40 | |
| 390. |
_ The function of a distributor in a coil ignition system of I.C. engines is$? |
| A. | To distribute spark |
| B. | To distribute power |
| C. | To distribute current |
| D. | To time the spark |
| Answer» E. | |
| 391. |
_ The air standard efficiency of an I.C. engine is given by (where r = Compression ratio, and γ = Ratio of specific heats)$? |
| A. | 1 - rγ - 1 |
| B. | 1 + rγ - 1 |
| C. | 1 - (1/rγ - 1) |
| D. | None of these |
| Answer» D. None of these | |
| 392. |
_ The firing order in an I.C. engine depends upon$? |
| A. | Arrangement of the cylinders |
| B. | Design of crankshaft |
| C. | Number of cylinders |
| D. | All of these |
| Answer» E. | |
| 393. |
_ The reflectivity depends upon$? |
| A. | Geometry of the reflector |
| B. | Energy of neutrons |
| C. | Properties of the reflector |
| D. | All of these |
| Answer» E. | |
| 394. |
_ A fuel of cetane number 40 has the same ignition quality as a mixture of$? |
| A. | 40% cetane and 60% alpha methyl naphthalene |
| B. | 40% alpha methyl naphthalene and 60% cetane |
| C. | 40% petrol and 60% diesel |
| D. | 40% diesel and 60% petrol |
| Answer» B. 40% alpha methyl naphthalene and 60% cetane | |
| 395. |
_ The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to$? |
| A. | Inject fuel in a chamber of high pressure at the end of compression stroke |
| B. | Inject fuel at a high velocity to facilitate atomization |
| C. | Ensure that penetration is not high |
| D. | All of the above |
| Answer» E. | |
| 396. |
_ The rating of a diesel engine, with increase in air inlet temperature, will$? |
| A. | Increase linearly |
| B. | Decrease linearly |
| C. | Increase parabolically |
| D. | Decrease parabolically |
| Answer» C. Increase parabolically | |
| 397. |
_ In a diesel engine, the duration between the time of injection and ignition, is known as$? |
| A. | Pre-ignition period |
| B. | Delay period |
| C. | Period of ignition |
| D. | Burning period |
| Answer» C. Period of ignition | |
| 398. |
_ Which of the following is false statement? Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following$? |
| A. | Piston ring and cylinder wear |
| B. | Formation of hard coating on piston skirts |
| C. | Oil sludge in the engine crank case |
| D. | Detonation |
| Answer» E. | |
| 399. |
__The theoretically correct air fuel ratio for petrol engine is of the order of__ |
| A. | 6: 1 |
| B. | 9: 1 |
| C. | 12: 1 |
| D. | 15: 1 |
| Answer» E. | |
| 400. |
__The fuels in order of decreasing knock tendency for spark ignition engines are__ |
| A. | Paraffin, aromatic, napthene |
| B. | Paraffin, napthene, aromatic |
| C. | Napthene, aromatics, paraffin |
| D. | Napthene, paraffin, aromatic |
| Answer» C. Napthene, aromatics, paraffin | |