MCQOPTIONS
Saved Bookmarks
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.
| 201. |
The size of inlet valve of an engine in comparison to exhaust valve is |
| A. | ore |
| B. | ess |
| C. | ame |
| D. | ore/less depending on capacity of engine |
| Answer» B. ess | |
| 202. |
The output of a diesel engine can be increased without increasing the engine revolution or size in following way |
| A. | eeding more fuel |
| B. | eating incoming air |
| C. | cavenging |
| D. | upercharging |
| Answer» E. | |
| 203. |
Which of the following does not relate to a spark ignition engine? |
| A. | gnition coil |
| B. | park plug |
| C. | arburettor |
| D. | uel injector |
| Answer» E. | |
| 204. |
Number of working strokes per min. for a two stroke cycle engine is _________ the speed of the engine in r.p.m. |
| A. | qual to |
| B. | ne-half |
| C. | wice |
| D. | our-times |
| Answer» B. ne-half | |
| 205. |
Number of working strokes per min. for a four stroke cycle engine are _________ the speed of the engine in r.p.m. |
| A. | qual to |
| B. | ne-half |
| C. | wice |
| D. | our-times |
| Answer» C. wice | |
| 206. |
Which of the following medium is compressed in a Diesel engine cylinder? |
| A. | ir alone |
| B. | ir and fuel |
| C. | ir and lub oil |
| D. | uel alone |
| Answer» B. ir and fuel | |
| 207. |
The specific fuel consumption per BH hour for a petrol engine is approximately |
| A. | .15 kg |
| B. | .2 kg |
| C. | .25 kg |
| D. | .3 kg |
| Answer» D. .3 kg | |
| 208. |
The air-fuel ratio in petrol engines is controlled by |
| A. | ontrolling valve opening/closing |
| B. | overning |
| C. | njection |
| D. | arburetion |
| Answer» E. | |
| 209. |
The air-fuel ratio of the petrol engine is controlled by |
| A. | uel pump |
| B. | overnor |
| C. | njector |
| D. | arburettor |
| Answer» E. | |
| 210. |
The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of |
| A. | orse test |
| B. | rony brake test |
| C. | otoring test |
| D. | eat balance test |
| Answer» B. rony brake test | |
| 211. |
The turbine of the turboprop engine is __________ that of the turbojet engine. |
| A. | ame as |
| B. | maller than |
| C. | igger than |
| D. | one of these |
| Answer» D. one of these | |
| 212. |
In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have |
| A. | ow density |
| B. | ow temperature |
| C. | ong ignition delay |
| D. | ll of these |
| Answer» E. | |
| 213. |
In a four stroke cycle engine, the sequence of operations is |
| A. | uction, compression, expansion and exhaust |
| B. | uction, expansion, compression and exhaust |
| C. | xpansion, compression, suction and exhaust |
| D. | ompression, expansion, suction and exhaust |
| Answer» B. uction, expansion, compression and exhaust | |
| 214. |
In a four stroke cycle diesel engine, the compression |
| A. | tarts at 40° after bottom dead center and ends at 10° before top dead center |
| B. | tarts at 40° before top dead center and ends at 40° after top dead center |
| C. | tarts at top dead center and ends at 40° before bottom dead center |
| D. | ay start and end anywhere |
| Answer» B. tarts at 40° before top dead center and ends at 40° after top dead center | |
| 215. |
The fuel valve in a four stroke cycle diesel engine |
| A. | pens at 15° after top dead center and closes at 20° before bottom dead center |
| B. | pens at 15° before top dead center and closes at 20° after top dead center |
| C. | pens at top dead center and closes at bottom dead center |
| D. | ay open and close anywhere |
| Answer» C. pens at top dead center and closes at bottom dead center | |
| 216. |
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to |
| A. | ncrease maximum pressure and maximum temperature |
| B. | educe maximum pressure and maximum temperature |
| C. | ncrease maximum pressure and decrease maximum temperature |
| D. | ecrease maximum pressure and increase maximum temperature |
| Answer» C. ncrease maximum pressure and decrease maximum temperature | |
| 217. |
In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as |
| A. | cavenging |
| B. | etonation |
| C. | upercharging |
| D. | olymerisation |
| Answer» B. etonation | |
| 218. |
The operation of forcing additional air under pressure into the engine cylinder is known as |
| A. | upercharging |
| B. | arburetion |
| C. | urbulence |
| D. | elay period |
| Answer» B. arburetion | |
| 219. |
Installation of supercharger on a four cycle diesel engine can result in the following percentage increase in power |
| A. | p to 35% |
| B. | p to 50% |
| C. | p to 75% |
| D. | p to 100% |
| Answer» E. | |
| 220. |
An engine indicator is used to determine the following |
| A. | peed |
| B. | emperature |
| C. | olume of cylinder |
| D. | .e.p. and I.H.P. |
| Answer» E. | |
| 221. |
A diesel engine, during suction stroke, draws |
| A. | ir only |
| B. | iesel only |
| C. | mixture of diesel and air |
| D. | one of these |
| Answer» B. iesel only | |
| 222. |
The object of providing masked inlet valve in the air passage of compression ignition engines is to |
| A. | nhance flow rate |
| B. | ontrol air flow |
| C. | nduce primary swirl |
| D. | nduce secondary turbulence |
| Answer» D. nduce secondary turbulence | |
| 223. |
Stoichiometric ratio is |
| A. | hemically correct air-fuel ratio by weight |
| B. | hemically correct air-fuel ratio by volume |
| C. | ctual air-fuel ratio for maximum efficiency |
| D. | one of the above |
| Answer» C. ctual air-fuel ratio for maximum efficiency | |
| 224. |
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. | uel pump |
| B. | uel injector |
| C. | park plug |
| D. | one of these |
| Answer» D. one of these | |
| 225. |
Detonation is harmful due to |
| A. | ncrease in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine |
| B. | xcessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls |
| C. | igh intensity of knock causes crankshaft vibration and the engine runs rough |
| D. | one of the above |
| Answer» E. | |
| 226. |
For the same compression ratio |
| A. | tto cycle is more efficient than the Diesel |
| B. | iesel cycle is more efficient than Otto |
| C. | oth Otto and Diesel cycles are, equally efficient |
| D. | ompression ratio has nothing to do with efficiency |
| Answer» B. iesel cycle is more efficient than Otto | |
| 227. |
The pressure inside the cylinder is _________ the atmospheric pressure during the exhaust stroke. |
| A. | qual to |
| B. | elow |
| C. | bove |
| D. | one of these |
| Answer» D. one of these | |
| 228. |
The self ignition temperature of petrol is _________ as compared to diesel oil. |
| A. | ame |
| B. | ower |
| C. | igher |
| D. | one of these |
| Answer» D. one of these | |
| 229. |
Compression ratio of I.C. Engines is |
| A. | he ratio of volumes of air in cylinder before compression stroke and after compression stroke |
| B. | olume displaced by piston per stroke and clearance volume in cylinder |
| C. | atio of pressure after compression and before compression |
| D. | wept volume/cylinder volume |
| Answer» B. olume displaced by piston per stroke and clearance volume in cylinder | |
| 230. |
A petrol engine has compression ratio from |
| A. | to 10 |
| B. | 0 to 15 |
| C. | 5 to 25 |
| D. | 5 to 40 |
| Answer» B. 0 to 15 | |
| 231. |
The air standard efficiency of an I.C. engine is given by (where r = Compression ratio, and γ = Ratio of specific heats) |
| A. | - rγ - 1 |
| B. | + rγ - 1 |
| C. | - (1/rγ - 1) |
| D. | one of these |
| Answer» D. one of these | |
| 232. |
The ignition of the charge by some hot surface within the engine before the passage of spark is called |
| A. | re-ignition |
| B. | etonation |
| C. | gnition delay |
| D. | uto-ignition |
| Answer» B. etonation | |
| 233. |
The firing order in an I.C. engine depends upon |
| A. | rrangement of the cylinders |
| B. | esign of crankshaft |
| C. | umber of cylinders |
| D. | ll of these |
| Answer» E. | |
| 234. |
Which of the following is false statement? Some of the methods used to reduce diesel smoke are as follows |
| A. | sing additives in the fuel |
| B. | ncreasing the compression ratio |
| C. | dherence to proper fuel specification |
| D. | voidance of overloading |
| Answer» C. dherence to proper fuel specification | |
| 235. |
The knocking tendency in compression ignition engines for a given fuel will be |
| A. | nhanced by decreasing compression ratio |
| B. | nhanced by increasing compression ratio |
| C. | ependent on other factors |
| D. | one of the above |
| Answer» B. nhanced by increasing compression ratio | |
| 236. |
Theoretically, a four stroke cycle engine should develop _________ power as that of a two stroke cycle engine. |
| A. | alf |
| B. | ame |
| C. | ouble |
| D. | our times |
| Answer» B. ame | |
| 237. |
Thermal efficiency of a two stroke cycle engine is _________ a four stroke cycle engine. |
| A. | qual to |
| B. | ess than |
| C. | reater than |
| D. | one of these |
| Answer» C. reater than | |
| 238. |
If V₁ is the jet velocity and V₀ is the vehicle velocity, then the propulsive efficiency of a rocket is given by |
| A. | 2(V₀/V₁)]/ [1 + (V₀/V₁)²] |
| B. | V₀/V₁)/ [1 + (V₀/V₁)²] |
| C. | ₀/(V₀+ V₁) |
| D. | ₁/(V₀+ V₁) |
| Answer» B. V₀/V₁)/ [1 + (V₀/V₁)²] | |
| 239. |
The following volume of air is required for consuming 1 liter of fuel by a four stroke engine |
| A. | m3 |
| B. | m3 |
| C. | 6 m3 |
| D. | 10 m3 |
| Answer» E. | |
| 240. |
Which of the following is not an intern’s combustion engine? |
| A. | -stroke petrol engine |
| B. | -stroke petrol engine |
| C. | iesel engine |
| D. | team turbine |
| Answer» E. | |
| 241. |
The process of breaking up or a liquid into fine droplets by spraying is called |
| A. | aporisation |
| B. | arburetion |
| C. | onization |
| D. | tomization |
| Answer» E. | |
| 242. |
The compression ignition engines are governed by |
| A. | it and miss governing |
| B. | ualitative governing |
| C. | uantitative governing |
| D. | ombination of (B) and (C) |
| Answer» C. uantitative governing | |
| 243. |
The spark ignition engines are governed by |
| A. | it and miss governing |
| B. | ualitative governing |
| C. | uantitative governing |
| D. | ombination of (B) and (C) |
| Answer» D. ombination of (B) and (C) | |
| 244. |
The pressure at the end of compression in the case of diesel engine is of the order of |
| A. | kg/cm |
| B. | 2 kg/cm |
| C. | 0 kg/cm |
| D. | 5 kg/cm |
| Answer» E. | |
| 245. |
The cetane number of diesel oil, generally available, is |
| A. | 0 to 25 |
| B. | 5 to 30 |
| C. | 0 to 40 |
| D. | 0 to 55 |
| Answer» E. | |
| 246. |
The ignition quality of diesel oil is expressed by |
| A. | etane number |
| B. | ctane number |
| C. | alorific value |
| D. | one of these |
| Answer» B. ctane number | |
| 247. |
Supercharging is the process of supplying the intake air to the engine cylinder at a density _________ the density of the surrounding atmosphere. |
| A. | qual to |
| B. | ess than |
| C. | reater than |
| D. | one of these |
| Answer» D. one of these | |
| 248. |
A diesel engine as compared to petrol engine (both running and rated load) is |
| A. | ore efficient |
| B. | ess efficient |
| C. | qually efficient |
| D. | ther factors will decide it |
| Answer» B. ess efficient | |
| 249. |
In a petrol engine, if diesel is used, then the engine will |
| A. | ot run |
| B. | un more efficiently |
| C. | un at high speed |
| D. | xplode |
| Answer» B. un more efficiently | |
| 250. |
Compression loss in I.C engines occurs due to |
| A. | eaking piston rings |
| B. | se of thick head gasket |
| C. | logged air inlet slots |
| D. | ll of the above |
| Answer» E. | |