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MCQOPTIONS
This section includes 4791 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 4201. |
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 | |
| 4202. |
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 | |
| 4203. |
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) | |
| 4204. |
If petrol is used in a diesel engine, then |
| A. | low power will be produced |
| B. | efficiency will be low |
| C. | higher knocking will occur |
| D. | black smoke will be produced |
| Answer» D. black smoke will be produced | |
| 4205. |
The sensing element in the control system of nuclear reactors measure the __________ of the neutron flux in the reactor. |
| A. | temperature |
| B. | volume |
| C. | density |
| D. | none of these |
| Answer» D. none of these | |
| 4206. |
If the temperature of intake air in internal combustion engine increases, then its efficiency will |
| A. | remain same |
| B. | decrease |
| C. | increase |
| Answer» C. increase | |
| 4207. |
The ignition quality of diesel oil is expressed by |
| A. | cetane number |
| B. | octane number |
| C. | calorific value |
| D. | none of these |
| Answer» B. octane number | |
| 4208. |
In a coil ignition system of petrol engines, a condenser is connected across the contact-breaker in order to |
| A. | prevent sparking across the gap between the points |
| B. | cause more rapid break of the primary current, giving a higher voltage in the secondary circuit |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 4209. |
In a four stroke cycle petrol engine, the expansion |
| A. | starts at top dead centre and ends at bottom dead centre |
| B. | starts at 30 before top dead centre and ends at 50 before bottom dead centre |
| C. | starts at 30 after top dead centre and ends at 50 after bottom dead centre |
| D. | may start and end anywhere |
| Answer» C. starts at 30 after top dead centre and ends at 50 after bottom dead centre | |
| 4210. |
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of |
| A. | 75% iso-octane and 25% normal heptane |
| B. | 75% normal heptane and 25% iso-octane |
| C. | 75% petrol and 25% diesel |
| D. | 75% diesel and 25% petrol |
| Answer» B. 75% normal heptane and 25% iso-octane | |
| 4211. |
The cylinder of a gas engine is made __________ than that of the petrol engine. |
| A. | smaller |
| B. | larger |
| Answer» C. | |
| 4212. |
The thermal efficiency of a petrol engine is __________ as compared to diesel engine. |
| A. | same |
| B. | less |
| C. | more |
| Answer» C. more | |
| 4213. |
The compression ignition engines are governed by |
| A. | hit and miss governing |
| B. | qualitative governing |
| C. | quantitative governing |
| D. | combination of (b) and (c) |
| Answer» C. quantitative governing | |
| 4214. |
The specific fuel consumption per B.P. hour for a diesel engine is about |
| A. | 0.2 kg |
| B. | 0.25 kg |
| C. | 0.3 kg |
| D. | 0.35 kg |
| Answer» B. 0.25 kg | |
| 4215. |
Detonation is harmful due to |
| A. | increase in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine |
| B. | excessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls |
| C. | high intensity of knock causes crankshaft vibration and the engine runs rough |
| D. | none of the above |
| Answer» E. | |
| 4216. |
The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in metres, N = Speed of engine in r.p.m., S - Spring balance reading in newtons, D = Dia. of brake drum in metres, and d = Dia. of rope in metres) |
| A. | <img src="/_files/images/mechanical-engineering/ic-engines-and-nuclear-power-plants/347-162-1.png"> |
| B. | <img src="/_files/images/mechanical-engineering/ic-engines-and-nuclear-power-plants/347-162-2.png"> |
| C. | <img src="/_files/images/mechanical-engineering/ic-engines-and-nuclear-power-plants/347-162-3.png"> |
| D. | all of these |
| Answer» E. | |
| 4217. |
A power plant giving least running cost of production of electrical power is |
| A. | steam power plant |
| B. | gas turbine power plant |
| C. | hydro electric power plant |
| D. | nuclear power plant |
| Answer» E. | |
| 4218. |
The thermal efficiency of petrol and gas engines is about |
| A. | 15% |
| B. | 30% |
| C. | 50% |
| D. | 70% |
| Answer» C. 50% | |
| 4219. |
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. | |
| 4220. |
The brake power is the power available |
| A. | in the engine cylinder |
| B. | at the crank shaft |
| C. | at the crank pin |
| D. | none of these |
| Answer» C. at the crank pin | |
| 4221. |
The slowing down of fast neutrons is desirable because slow moving neutrons are more effective than fast neutrons in triggering fission. |
| A. | Agree |
| B. | Disagree |
| Answer» B. Disagree | |
| 4222. |
In petrol engines, using a fixed octane rating fuel, the increase in engine speed will decrease the knocking tendency. |
| A. | Yes |
| B. | No |
| Answer» B. No | |
| 4223. |
Materials which make good moderators do not make good reflectors. |
| A. | Correct |
| B. | Incorrect |
| Answer» C. | |
| 4224. |
The ignition of the charge by some hot surface within the engine before the passage of spark is called |
| A. | pre-ignition |
| B. | detonation |
| C. | ignition delay |
| D. | auto-ignition |
| Answer» B. detonation | |
| 4225. |
Special reactors, called breeder reactors, supply a net gain of fissionable material. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4226. |
In diesel engines, the ignition takes place due to the heat produced in the engine cylinder at the end of compression. |
| A. | Correct |
| B. | Incorrect |
| Answer» B. Incorrect | |
| 4227. |
In a four stroke cycle diesel engine, the compression |
| A. | starts at 40 after bottom dead centre and ends at 10 before top dead centre |
| B. | starts at 40 before top dead centre and ends at 40 after top dead centre |
| C. | starts at top dead centre and ends at 40 before bottom dead centre |
| D. | may start and end anywhere |
| Answer» B. starts at 40 before top dead centre and ends at 40 after top dead centre | |
| 4228. |
In a four stroke cycle diesel engine, the inlet valve |
| A. | opens at 20 before top dead centre and closes at 40 after bottom dead centre |
| B. | opens at 20 after top dead centre and closes at 20 before bottom dead centre |
| C. | opens at top dead centre and closes at bottom dead centre |
| D. | may open and close anywhere |
| Answer» B. opens at 20 after top dead centre and closes at 20 before bottom dead centre | |
| 4229. |
The knocking in diesel engines may be prevented by |
| A. | reducing the delay period |
| B. | raising the compression ratio |
| C. | increasing the inlet pressure of air |
| D. | all of these |
| Answer» E. | |
| 4230. |
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 | |
| 4231. |
The normal heptane (C7H16) is given a rating of __________ octane number. |
| A. | 0 |
| B. | 50 |
| C. | 100 |
| D. | 120 |
| Answer» B. 50 | |
| 4232. |
The ratio of the indicated thermal efficiency to the air standard efficiency is known as |
| A. | mechanical efficiency |
| B. | overall efficiency |
| C. | volumetric efficiency |
| D. | relative efficiency |
| Answer» E. | |
| 4233. |
A petrol engine has compression ratio from |
| A. | 6 to 10 |
| B. | 10 to 15 |
| C. | 15 to 25 |
| D. | 25 to 40 |
| Answer» B. 10 to 15 | |
| 4234. |
The fuels in order of decreasing knock tendency for spark ignition engines are |
| A. | paraffins, aromatics, napthenes |
| B. | paraffins, napthenes, aromatics |
| C. | napthenes, aromatics, paraffins |
| D. | napthenes, paraffins, aromatics |
| Answer» C. napthenes, aromatics, paraffins | |
| 4235. |
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 | |
| 4236. |
Which of the following statement is correct regarding the features of a Breeder reactor? |
| A. | It produces more fuel than it consumes. |
| B. | It requires highly enriched fuel. |
| C. | It requires liquid sodium metal as moderator. |
| D. | all of the above |
| Answer» E. | |
| 4237. |
By higher octane number of spark ignition fuel, it is meant that the fuel has |
| A. | higher heating value |
| B. | higher flash point |
| C. | lower volatility |
| D. | longer ignition delay |
| Answer» E. | |
| 4238. |
Which one of the following engines will have heavier flywheel than the remaining ones? |
| A. | 30 kW four-stroke petrol engine running at 1500 r.p.m. |
| B. | 30 kW two-stroke petrol engine running at 1500 r.p.m. |
| C. | 30 kW two-stroke diesel engine running at 750 r.p.m. |
| D. | 30 kW four-stroke diesel engine running at 750 r.p.m. |
| Answer» B. 30 kW two-stroke petrol engine running at 1500 r.p.m. | |
| 4239. |
The air-fuel ratio of the petrol engine is controlled by |
| A. | carburettor |
| B. | injector |
| C. | governor |
| D. | none of these |
| Answer» B. injector | |
| 4240. |
The relative efficiency of an I.C. engine is the ratio of the indicated thermal efficiency to the air standard efficiency. |
| A. | Correct |
| B. | Incorrect |
| Answer» B. Incorrect | |
| 4241. |
A long delay period in compression ignition engines gives a more rapid rise in pressure which causes knocking. |
| A. | Yes |
| B. | No |
| Answer» B. No | |
| 4242. |
Thermal efficiency of a two stroke cycle engine is __________ a four stroke cycle engine. |
| A. | equal to |
| B. | less than |
| C. | greater than |
| Answer» C. greater than | |
| 4243. |
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 | |
| 4244. |
Which of the following statement is correct regarding normal cetaine? |
| A. | It is a standard fuel used for knock rating of diesel engines. |
| B. | Its chemical name is normal-hexadecane. |
| C. | It has long carbon chain structure. |
| D. | all ofthe above |
| Answer» E. | |
| 4245. |
Enriched uranium is required as a fuel in a nuclear reactor, if light water is used as moderator and coolant, because light water has |
| A. | high neutron absorption cross-section |
| B. | low moderating efficiency |
| C. | high neutron scatter cross-section |
| D. | low neutron absorption cross-section |
| Answer» C. high neutron scatter cross-section | |
| 4246. |
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to |
| A. | increase maximum pressure and maximum temperature |
| B. | reduce maximum pressure and maximum temperature |
| C. | increase maximum pressure and decrease maximum temperature |
| D. | decrease maximum pressure and increase maximum temperature |
| Answer» C. increase maximum pressure and decrease maximum temperature | |
| 4247. |
The __________ engines can work on very lean mixture of fuel. |
| A. | spark ignition |
| B. | compression ignition |
| Answer» C. | |
| 4248. |
During suction stroke of a four stroke petrol engine, the inlet valve opens and the charge is sucked into the cylinder as the piston moves upwards from the bottom dead centre. |
| A. | True |
| B. | False |
| Answer» C. | |
| 4249. |
The power actually developed by the engine cylinder of an I.C. engine is known as |
| A. | theoretical power |
| B. | actual power |
| C. | indicated power |
| D. | none of these |
| Answer» D. none of these | |
| 4250. |
A supercharger receives air from the atmosphere surrounding the engine, compresses it to a higher pressure and then feeds it into the inlet valve of the engine. |
| A. | Correct |
| B. | Incorrect |
| Answer» B. Incorrect | |