McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 201. |
The knock in diesel engine occurs due to |
| A. | instantaneous and rapid burning of the first part of the charge |
| B. | instantaneous atuo iginition of last part of charge |
| C. | delayed burning of the first part of the charge |
| D. | reduction of delay period |
| Answer» A. instantaneous and rapid burning of the first part of the charge | |
| 202. |
A stoichiometric air-fuel ratio is |
| A. | chemically correct mixture |
| B. | lean mixture |
| C. | rich mixture for idling |
| D. | rich mixture for over loads |
| Answer» A. chemically correct mixture | |
| 203. |
Mechanical efficiency is the ratio of |
| A. | brake power to heat input |
| B. | indicated power to heat input |
| C. | brake power to indicated power |
| D. | friction loss to heat input |
| Answer» C. brake power to indicated power | |
| 204. |
Most commonly used lubrication system in automobiles is the |
| A. | splash system |
| B. | pressure system |
| C. | petrol system |
| D. | gravity system |
| Answer» B. pressure system | |
| 205. |
Friction that occurs between the layers of oil film is called |
| A. | viscous friction |
| B. | greasy friction |
| C. | dry friction |
| D. | boundary friction |
| Answer» A. viscous friction | |
| 206. |
Crankcase ventilation, is provided |
| A. | to cool cylinder |
| B. | to cool crankcase |
| C. | to cool piston |
| D. | to remove blow by |
| Answer» D. to remove blow by | |
| 207. |
the most important property of the lubricant is |
| A. | density |
| B. | viscosity |
| C. | thermal conductivity |
| D. | none of the above |
| Answer» B. viscosity | |
| 208. |
The maximum pressure in the lubrication system is controlled by |
| A. | oil pump |
| B. | oil filter |
| C. | valve relief |
| D. | supply voltage |
| Answer» C. valve relief | |
| 209. |
The lubricants commonly used in the automobiles are |
| A. | animal oils |
| B. | vegetable oils |
| C. | mineral oils |
| D. | cooking oils |
| Answer» B. vegetable oils | |
| 210. |
Detergents are oil additives used to |
| A. | reduce viscosity |
| B. | increase fire point |
| C. | prevent sludge formation |
| D. | prevent foaming |
| Answer» C. prevent sludge formation | |
| 211. |
Oil pressure in the dry sump lubrication system is around |
| A. | 5 bar - 10 bar |
| B. | 11 bar 15 bar |
| C. | 3 bar - 8 bar |
| D. | 1 bar |
| Answer» C. 3 bar - 8 bar | |
| 212. |
For mep decreases when using |
| A. | single cylinder engine |
| B. | smaller number of larger cylinders |
| C. | larger number of smaller cylinders |
| D. | none of the above |
| Answer» C. larger number of smaller cylinders | |
| 213. |
With increase in compression ratio, mechanical efficiency |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | compression ratio has nothing to do with ƞmech |
| Answer» A. increases | |
| 214. |
Blow by losses are |
| A. | directly proportional to the inlet pressure |
| B. | inversely proportional to the inlet pressure |
| C. | proportional to the square root of inlet pressure |
| D. | none of the above |
| Answer» C. proportional to the square root of inlet pressure | |
| 215. |
Mist lubrication system is mainly used in |
| A. | four-stroke petrol engine |
| B. | four-stroke diesel engine |
| C. | two-stroke petrol engine |
| D. | Wankle engine |
| Answer» C. two-stroke petrol engine | |
| 216. |
Additives are added in lubricant to have |
| A. | detergent-dispersant characteristics |
| B. | pour point depression |
| C. | antifoam characteristics |
| D. | all of the above |
| Answer» D. all of the above | |
| 217. |
The principal surfaces requiring lubrication in an IC engine are |
| A. | cylinder head |
| B. | crankcase |
| C. | inlet and exhaust manifold |
| D. | none of the above |
| Answer» D. none of the above | |
| 218. |
The heat given to cooling medium in IC engines is about |
| A. | 50-60% |
| B. | 30-40% |
| C. | 10-20% |
| D. | 60-70% |
| Answer» B. 30-40% | |
| 219. |
Radiator is provided to |
| A. | cool the jacket water |
| B. | pressurise the cooling water |
| C. | provide additional water flow |
| D. | none of the above |
| Answer» A. cool the jacket water | |
| 220. |
Thermostat is used in radiators to |
| A. | control the velocity of water |
| B. | control distribution of water to various cylinders |
| C. | control the water temperature |
| D. | control the pressure of water |
| Answer» C. control the water temperature | |
| 221. |
As the compression ratio increases, there is a |
| A. | large increase in heat rejection |
| B. | large decrease in heat reduction |
| C. | marginal increase in heat rejection |
| D. | marginal reduction in heat rejection |
| Answer» D. marginal reduction in heat rejection | |
| 222. |
Spark timing other than minimum spark advance for best torque (MBT) results in |
| A. | less heat rejection |
| B. | more beat rejection |
| C. | no effect on heat rejection |
| D. | none of the above |
| Answer» B. more beat rejection | |
| 223. |
Direct system of cooling air is one which |
| A. | cooling water flows by gravity |
| B. | hot water is continuously cooled and circulated |
| C. | hot water is simply discharged |
| D. | water is allowed to evaporate in the cylinder jacket |
| Answer» C. hot water is simply discharged | |
| 224. |
In evaporate cooling systems, heat absorbed per kg of coolant air is equal to |
| A. | Cp Δ t |
| B. | Cv Δ t |
| C. | latent heat of the coolant |
| D. | (Cp – Cv) Δ t |
| Answer» C. latent heat of the coolant | |
| 225. |
Pump used in the forced cooling system is normally |
| A. | piston pump |
| B. | gear pump |
| C. | vane pump |
| D. | centrifugal pump |
| Answer» D. centrifugal pump | |
| 226. |
Limitations of air cooling systems are |
| A. | applicable only to large engines |
| B. | cooling is fast |
| C. | higher working temperature compared to water cooling |
| D. | all of the above |
| Answer» C. higher working temperature compared to water cooling | |
| 227. |
Which is more viscous lib oil |
| A. | SEA 30 |
| B. | SAE 40 |
| C. | SAE 50 |
| D. | SAE 80. |
| Answer» D. SAE 80. | |
| 228. |
In a naturally aspirated diesel engine, the air is supplied by |
| A. | a supercharger |
| B. | a centrifugal blower |
| C. | a vacuum chamber |
| D. | an injection tube |
| Answer» C. a vacuum chamber | |
| 229. |
The measurement of frictional power by Willans line is applicable only to |
| A. | SI engines at a particular speed |
| B. | CI engines at a particular speed |
| C. | any engine at a particular speed only |
| D. | none of the above |
| Answer» B. CI engines at a particular speed | |
| 230. |
Morse test is applicable only to |
| A. | single cylinder SI engines |
| B. | single cylinder CI engines |
| C. | multicylinder CI engines |
| D. | single and multicylinder SI and CI engines |
| Answer» C. multicylinder CI engines | |
| 231. |
The most accurate method of determining fp is by |
| A. | Willan's line |
| B. | Morse test |
| C. | measurement of brake and indicated power |
| D. | motoring test |
| Answer» C. measurement of brake and indicated power | |
| 232. |
In the air box method of measuring air flow, the air box is provided to |
| A. | have constant temperature |
| B. | have constant flow |
| C. | damp out the pulsations |
| D. | provide constant velocity of flow |
| Answer» C. damp out the pulsations | |
| 233. |
The air box/swept volume ratio should be in the range for single-cylinder engines |
| A. | 10- 100% |
| B. | 200-300% |
| C. | 500 600% |
| D. | > 1000% |
| Answer» C. 500 600% | |
| 234. |
The best method of measuring speed is by |
| A. | mechanical tachometer |
| B. | electrical tachometer |
| C. | magnetic pickup |
| D. | none of the above |
| Answer» C. magnetic pickup | |
| 235. |
Flame ionization detector is used for measuring |
| A. | CO |
| B. | HC |
| C. | NOx |
| D. | CO2 |
| Answer» B. HC | |
| 236. |
Chemilumine scence analyzer is used for measuring |
| A. | NOx |
| B. | CO |
| C. | HC |
| D. | CO2 |
| Answer» A. NOx | |
| 237. |
Non-dispersive infra-red analyzer is widely accepted instrument for measuring |
| A. | NO |
| B. | HC |
| C. | CO |
| D. | CO2 |
| Answer» C. CO | |
| 238. |
Thermal efficiency varies |
| A. | inversely as sfc |
| B. | directly as sfc |
| C. | as square as sfc |
| D. | as root as sfc |
| Answer» A. inversely as sfc | |
| 239. |
Mechanical efficiency is ratio of |
| A. | fp to bp |
| B. | fp to ip |
| C. | bp to ip |
| D. | ip to fp |
| Answer» C. bp to ip | |
| 240. |
For N is the rpm, number of power strokes per minute in a four-stroke engine is |
| A. | 2N |
| B. | N/2 |
| C. | N |
| D. | 4N |
| Answer» B. N/2 | |
| 241. |
If N is the rpm, number of power strokes per minute in a two-stroke engine is |
| A. | N |
| B. | 2N |
| C. | N/2 |
| D. | 4N |
| Answer» A. N | |
| 242. |
The spark timing and combustion rate should be such that |
| A. | peak pressure occurs at TDC |
| B. | one half of the total pressure occurs at TDC |
| C. | ignition delay is reduced |
| D. | none of the above |
| Answer» B. one half of the total pressure occurs at TDC | |
| 243. |
Volumetric efficiency is a measure of |
| A. | speed of the engine |
| B. | power of the engine |
| C. | breathing capacity of the engine |
| D. | pressure rise in the cylinder |
| Answer» C. breathing capacity of the engine | |
| 244. |
Indicated power is directly proportional to |
| A. | torque |
| B. | air consumption |
| C. | cylinder peak pressure |
| D. | none of the above |
| Answer» B. air consumption | |
| 245. |
Turbocharger engines are those in which charge density is increased by |
| A. | separate air compressors |
| B. | compressors driven by exhaust gas turbine |
| C. | cooling inlet air |
| D. | none of the above |
| Answer» B. compressors driven by exhaust gas turbine | |
| 246. |
Brake thermal efficiency of SI engine is in the range |
| A. | 35% to 60% |
| B. | 25% to 35% |
| C. | 60% to 80% |
| D. | none of the above |
| Answer» B. 25% to 35% | |
| 247. |
The volumetric efficiency of a well-designed engine is in the range |
| A. | 30 to 40% |
| B. | 40 to 609% |
| C. | 60 to 70% |
| D. | 75 to 90% |
| Answer» D. 75 to 90% | |
| 248. |
The major contributor of Carbon monoxide is |
| A. | Motor vehicle |
| B. | Industrial processes |
| C. | Stationary fuel combustion |
| D. | None of the above |
| Answer» A. Motor vehicle | |
| 249. |
Apart from hydrocarbons, the main pollutants in the engine exhaust are |
| A. | CO and CO2 |
| B. | CO2 and NOx |
| C. | CO and NOx |
| D. | CO2 and H2O |
| Answer» C. CO and NOx | |
| 250. |
Maximum allowable hydrocarbon in the car emission are approximately |
| A. | 10 ppm |
| B. | 100 ppm |
| C. | 1000 ppm |
| D. | 5000 ppm |
| Answer» B. 100 ppm | |
Done Studing? Take A Test.
Great job completing your study session! Now it's time to put your knowledge to the test. Challenge yourself, see how much you've learned, and identify areas for improvement. Don’t worry, this is all part of the journey to mastery. Ready for the next step? Take a quiz to solidify what you've just studied.