McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 251. |
Which of the boiler provides superheated steam? |
| A. | Locomotive boiler |
| B. | Lancashire boiler |
| C. | Cornish boiler |
| D. | All of the above |
| E. | None of the above |
| Answer» A. Locomotive boiler | |
| 252. |
Which of the following particles will be smallest in size? |
| A. | Drizzle |
| B. | Mist |
| C. | Smog |
| D. | Fog |
| E. | Rain |
| Answer» C. Smog | |
| 253. |
Dew point temperature is an indication of |
| A. | Condition of air |
| B. | Condition of moisture in air |
| C. | Dryness of air |
| D. | Lowest temperature where air and water vapour start separating |
| E. | Moisture constant of air |
| Answer» D. Lowest temperature where air and water vapour start separating | |
| 254. |
High air-fuel ratio in gas turbines |
| A. | Reduces the exhaust temperature |
| B. | Improves thermal efficiency |
| C. | Increases power output |
| D. | Restricts damage to turbine blades |
| E. | None of the above |
| Answer» A. Reduces the exhaust temperature | |
| 255. |
If a steam injector fails to lift the water the trouble may not be due to |
| A. | Too low steam pressure for list |
| B. | Water pipe clogged |
| C. | Water supply to cold |
| D. | End of water pipe not submerged |
| E. | None of the above |
| Answer» C. Water supply to cold | |
| 256. |
Working in the cryogenic range means dealing with temperatures |
| A. | Below absolute zero |
| B. | Below zero degree centigrade |
| C. | Between - 190?C and absolute zero |
| D. | Prevailing normally in the atomsphere |
| E. | Between zero degree centigrade and 190?C |
| Answer» C. Between - 190?C and absolute zero | |
| 257. |
The sulphur content in diesel oil should not exceed |
| A. | 15% |
| B. | 5% |
| C. | 12% |
| D. | 1% |
| E. | 10% |
| Answer» D. 1% | |
| 258. |
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» A. Chain in great stoker | |
| 259. |
The governor for steam turbine is driven by |
| A. | Main shaft |
| B. | Separate motor |
| C. | Belt drive |
| D. | Feed pump motor |
| E. | None of the above |
| Answer» A. Main shaft | |
| 260. |
Air preheater in a boiler will be invariably located between |
| A. | Condenser and feed water pump |
| B. | Water treatment plant and furnace |
| C. | Boiler furnace and chimney |
| D. | Economiser and feed pump |
| E. | Forced draft fan and furnace |
| Answer» E. Forced draft fan and furnace | |
| 261. |
A run-of-river hydro-electric station is one which is |
| A. | Located on a small river |
| B. | Located on a river which does not flow throughout the year |
| C. | Located on a steam flow without water storage |
| D. | Locted on a steam flow with large water storage |
| E. | None of the above |
| Answer» C. Located on a steam flow without water storage | |
| 262. |
After cooler is used to |
| A. | Cool the air |
| B. | Reduce the volume of air |
| C. | To cause moisture and oil vapour to drop out |
| D. | Remove impurities from air |
| E. | None of the above |
| Answer» A. Cool the air | |
| 263. |
Brayton cycle cannot be used in reciprocating engines even for same compression rations and work output because |
| A. | Large volume at low pressure cannot be efficiently harded in reciprocating engines |
| B. | Brayton cycle is less efficient |
| C. | Otto cycle is more efficient |
| D. | Brayton cycle requires large air-fuel ratio |
| E. | Brayton cycle is for slow speed engines only |
| Answer» A. Large volume at low pressure cannot be efficiently harded in reciprocating engines | |
| 264. |
A sample having pH value of 5 will be |
| A. | Neutral |
| B. | Acidic |
| C. | Alkalino |
| E. | None of the above |
| Answer» B. Acidic | |
| 265. |
The mean effective pressure of a diesel cycle having fixed compression ratio will increase if cut off ratio will |
| A. | Increase |
| B. | Decrease |
| C. | Independent of CR |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» A. Increase | |
| 266. |
Thermal efficiency of C.I. engines on weak mixtures is |
| A. | Higher |
| B. | Lower |
| C. | Unaffected |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» A. Higher | |
| 267. |
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» D. Atomization | |
| 268. |
A negative loop in the P-V diagram of a petrol engine is due to |
| A. | Carbon dioxide |
| B. | Suction of air |
| C. | pre-ignition |
| D. | early opening of exnaust valve |
| E. | detonation |
| Answer» D. early opening of exnaust valve | |
| 269. |
A compound pressure gauge measures |
| A. | Average pressure |
| B. | Positive and negative pressures |
| C. | Compound pressures |
| D. | Variable pressures |
| E. | Complex pressures |
| Answer» B. Positive and negative pressures | |
| 270. |
A barN is |
| A. | A unit of area |
| B. | A unit of length |
| C. | A unit of time |
| D. | A unit of mass |
| E. | None of the above |
| Answer» A. A unit of area | |
| 271. |
In isothermal compression |
| A. | There is no gain internal energy |
| B. | Temperature increses very slowly |
| C. | There is no exchange of heat with environment |
| D. | Entropy changes is zero |
| E. | None of the above |
| Answer» A. There is no gain internal energy | |
| 272. |
In Parsons reaction turbine |
| A. | The fixed and moving blades are identical |
| B. | The velocity biagram is unsymmetrical about a vertical centre line |
| C. | The degree of reaction is |
| D. | The fixed blades are smaller in size as compared to moving blades |
| E. | The fixed blades are larger in size compared to fixed blades |
| Answer» A. The fixed and moving blades are identical | |
| 273. |
For combustion of one kg of carbon the quantity of oxygen required (air contains 23% by wight of oxygen) is |
| A. | 12 kg |
| B. | 8 kg |
| C. | 2.62 kg |
| D. | 11.6 kg |
| E. | 3.67 kg |
| Answer» C. 2.62 kg | |
| 274. |
If a engine working on Otto cycle has its compression ratio raised from 5 to 6 the percentage increase in air standard efficiency will be |
| A. | 4% |
| B. | 10% |
| C. | 6% |
| D. | 8% |
| E. | 1% |
| Answer» A. 4% | |
| 275. |
For spark ignition engines fuel in order of decreasing knock tendency are |
| A. | Paraffins, aromatics, naphthenes |
| B. | Paraffins, naphthenes, armatics |
| C. | Aromatics, paraffins, naphthenes |
| D. | Naphthenes, aromatics, paraffins |
| E. | Naphthenes, paraffins |
| Answer» B. Paraffins, naphthenes, armatics | |
| 276. |
Which of the following can have octane rating of more than 100? |
| A. | Gobar gas |
| B. | Normal petrol |
| C. | Methyl alcohol |
| D. | Benzol |
| E. | Ethyl alcohol |
| Answer» D. Benzol | |
| 277. |
Normally the colour of exhaust from a diesel engine is |
| A. | Bluish |
| B. | Reddish |
| C. | Violet |
| D. | Black |
| E. | Yellowish |
| Answer» D. Black | |
| 278. |
For initially dry and saturated steam flowing through a nozzle the volue of critical pressure ratio is given by |
| A. | 0.577 |
| B. | 1 |
| C. | 0.528 |
| D. | 0.546 |
| E. | 0.75 |
| Answer» A. 0.577 | |
| 279. |
Which of the following type of internal combustion engines uses rocker arms? |
| A. | Radial engines |
| B. | Side valve engines |
| C. | Overhead valve engines |
| D. | Stationary engines |
| E. | All of the above |
| Answer» C. Overhead valve engines | |
| 280. |
In naturally aspirated engine the pressure inside cylinder at the end of suction stroke is |
| A. | Less than atmospheric |
| B. | Same as atmospheric |
| C. | More than atmospheric |
| D. | Depends on atmospheric conditions |
| E. | None of the above |
| Answer» A. Less than atmospheric | |
| 281. |
The ash content in diesel oil should not exceed |
| A. | 0.10% |
| B. | 0.50% |
| C. | 5% |
| D. | 0.01% |
| E. | 1% |
| Answer» D. 0.01% | |
| 282. |
A hot short metal is |
| A. | Brittle when heated |
| B. | Brittle when cold |
| C. | Ductile at low temperatures |
| D. | Ductile at high temperatures |
| E. | None of the above |
| Answer» A. Brittle when heated | |
| 283. |
In a SI engine the advancing of spark timing will |
| A. | Increase knocking tendency |
| B. | Reduce knocking tendency |
| C. | Not have any effect |
| D. | Depends on intensity of spark only |
| E. | None of the above |
| Answer» A. Increase knocking tendency | |
| 284. |
Of the calorific value ranges given below which one is generally for coal? |
| A. | 2500 - 4000 kcal/kg |
| B. | 1000 - 2500 kcal/kg |
| C. | 4000 - 7000 kcal/kg |
| D. | 8000 - 12000 kcal/kg |
| E. | 100 - 1000 kcal/kg |
| Answer» C. 4000 - 7000 kcal/kg | |
| 285. |
The function of a piston rins in an internal combustion engine is |
| A. | To prevent lubricating oil from entering the combustion space |
| B. | To prevent leakage of combustion chamber products |
| C. | To transfer heat from piston to cylinder walls |
| D. | All of the above |
| E. | None of the above |
| Answer» D. All of the above | |
| 286. |
Zeroth law of thermodynamics states that |
| A. | Two systems are always in equilibrium |
| B. | If two systems are in equilibrium the third system will also be in equilibrium |
| C. | If two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other |
| D. | Two systems not in equilibrium with a third system are also not in equilibrium with each other |
| E. | None of the above |
| Answer» C. If two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other | |
| 287. |
For the same peak pressure and 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» B. Diesel cycle is more efficient | |
| 288. |
In a jet propulsion unit the products of combustion after passing through the gas turbine are discharged into |
| A. | Recycled back to compressor |
| B. | Atmosphere |
| C. | Compressor |
| D. | Vacuum |
| E. | Discharge nozzle |
| Answer» E. Discharge nozzle | |
| 289. |
A D-slide valve is used in |
| A. | Two stroke engines |
| B. | Diesel engines |
| C. | Petrol engines |
| D. | Steam engines |
| E. | Double acting engines |
| Answer» D. Steam engines | |
| 290. |
The Clapeyron equation is applicable for |
| A. | System in equilibrium |
| B. | Change of state |
| C. | Change of state when two phases are in equilibrium |
| D. | Change of state when water and water vapours are involved |
| E. | None of the above |
| Answer» C. Change of state when two phases are in equilibrium | |
| 291. |
Speed drop is the |
| A. | Drop in engine speed |
| B. | Increasing in engine speed |
| C. | Reduction in engine speed from no loads to full load |
| D. | Change in engine speed while fuel supply remains the same |
| E. | None of the above |
| Answer» C. Reduction in engine speed from no loads to full load | |
| 292. |
For reciprocating air compressor the law of compression desired is isothermal and that may be possible by |
| A. | Very high speeds |
| B. | very low speeds |
| C. | any speed as speed does not affect the compression law |
| D. | None of the above |
| E. | Carbon dioxide |
| Answer» B. very low speeds | |
| 293. |
In a surface condenser near to the air pump suction the vacuum is 500 mm of mercury with 730 mm of mercury height in a barometer. The pressure near the air pump suction would be |
| A. | 0.69 kg/sq-cm |
| B. | 1.213 kg/sq-cm |
| C. | 0.313 kg/sq-cm |
| D. | 0.687 kg/sq-cm |
| E. | 1230 mm Hg |
| Answer» A. 0.69 kg/sq-cm | |
| 294. |
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» A. Alcohol | |
| 295. |
If performance of SI engines of different manufacture having different capacities, sizes and systems are to be compared the common parameter would be |
| A. | Engine cylinder diameter |
| B. | B.H.P. |
| C. | Weight of engine |
| D. | Speed |
| E. | Mean effective pressure |
| Answer» E. Mean effective pressure | |
| 296. |
Which of the following is not a part of diesel engine? |
| A. | Gudgeon pin |
| B. | Air filter |
| C. | Oil pump |
| D. | Condenser |
| E. | Lubricating oil filter |
| Answer» D. Condenser | |
| 297. |
Compression ratio for spark ignition engines varies in the range |
| A. | 6 to 12 |
| B. | 20 to 25 |
| C. | 4 to 6 |
| D. | 25 to 30 |
| E. | 12 to 20 |
| Answer» A. 6 to 12 | |
| 298. |
If a heat engine given an output of 3.5 kW and input is 10000 Joules per second, the thermal efficiency of the engine will be |
| A. | 66?% |
| B. | 35% |
| C. | 30% |
| D. | 65% |
| E. | 55% |
| Answer» B. 35% | |
| 299. |
Inlet valve of a IC engine remains open for |
| A. | 180? |
| B. | 250? |
| C. | 300? |
| D. | 150? |
| E. | 280? |
| Answer» B. 250? | |
| 300. |
The capacity of an automobile battery is expressed in terms of |
| A. | Number of cells |
| B. | Number of plate |
| C. | Ampere hours |
| D. | Amperes |
| E. | Voltage |
| Answer» C. Ampere hours | |
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