MCQOPTIONS
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MCQOPTIONS
This section includes 460 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Engines knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Air fuel ratio in a petrol engine fitted with dirty air cleaner as compared to that with clean air clearance will be |
| A. | Not affected |
| B. | Higher |
| C. | Lower |
| D. | Fluctuating |
| E. | Depends on load |
| Answer» D. Fluctuating | |
| 202. |
If a water cooled compressor knocks during operation, the probable cause cannot be |
| A. | Loose valve |
| B. | Air filter choked |
| C. | Too much clearance in crank pin |
| D. | Excess cooling in intercooler |
| E. | Loose flywheel or pulley |
| Answer» E. Loose flywheel or pulley | |
| 203. |
The ends of piston rod in steam engines are connected to |
| A. | Connecting rod and cross-head |
| B. | Crankshaft and cross-head |
| C. | Piston and crankshaft |
| D. | Piston and cross-head |
| E. | Connecting rod and crankshaft |
| Answer» E. Connecting rod and crankshaft | |
| 204. |
Thermal efficiency of a compression ignition engine may be of the order of |
| A. | 35% |
| B. | 50% |
| C. | 20% |
| D. | 75% |
| E. | 70% |
| Answer» B. 50% | |
| 205. |
Which one of the following factors will not assist in smooth running of a compression ignition engine? |
| A. | Moderate rate of pressure rise |
| B. | Short delay period |
| C. | Minimum of after burning |
| D. | High ignition temperature of fuel |
| E. | None of the above |
| Answer» E. None of the above | |
| 206. |
In case of an opposed piston engine the combustion chamber |
| A. | Is not provided |
| B. | Is formed between two piston tops |
| C. | Is provided towards crank case side |
| D. | Is fitted outside the cylinder |
| E. | None of the above |
| Answer» C. Is provided towards crank case side | |
| 207. |
The supercharging of diesel engine is done mainly to |
| A. | Cool the engine |
| B. | Increase the life of the engine |
| C. | Increase the power output |
| D. | Increase the speed |
| E. | Reduce the cnoise from the engine |
| Answer» D. Increase the speed | |
| 208. |
Maintenance requirements are least in case of |
| A. | Electric locomotives |
| B. | Carbon dioxide |
| C. | Diesel locomotives |
| D. | Steam locomotives |
| Answer» B. Carbon dioxide | |
| 209. |
In jet engine the compression ratio |
| A. | Varies with altitude |
| B. | Varies with speed |
| C. | Varies as square of speed |
| D. | Remains constant |
| E. | None of the above |
| Answer» D. Remains constant | |
| 210. |
For same compression ratio and same heat input |
| A. | Otto cycle is more efficient |
| B. | Diesel cycle is more efficient |
| C. | Both are equally efficient |
| D. | None of the above |
| Answer» B. Diesel cycle is more efficient | |
| 211. |
Blue smoke from a diesel engine indicates the presence of |
| A. | Unburnt carbon |
| B. | Unburnt oil |
| C. | Carbon dioxide |
| D. | Carbon monoxide |
| E. | Nitrous oxide |
| Answer» C. Carbon dioxide | |
| 212. |
Crankshafts are generally |
| A. | Turned from bar stock |
| B. | Die cast |
| C. | Sand cast |
| D. | Forged |
| E. | Cold headed |
| Answer» E. Cold headed | |
| 213. |
For the same power and same speed, the flywheel of a two stroke engine as compared to that of a four stroke engine will be |
| A. | There is no correlation |
| B. | Same size |
| C. | Small |
| D. | Bigger |
| E. | Different shape |
| Answer» E. Different shape | |
| 214. |
Normally the colour of exhaust from a petrol engine is |
| A. | Reddish |
| B. | Black |
| C. | Yellowish |
| D. | Bluish |
| E. | Violet |
| Answer» E. Violet | |
| 215. |
If the performance of diesel engines of different sizes, cylinder dimensions and horse power ratings are to be compared, which of the following parameter can be used for such comparison? |
| A. | Air-fuel ratio |
| B. | Brake specific fuel consumption |
| C. | Volumetric efficiency |
| D. | Swept volume |
| E. | None of the above |
| Answer» C. Volumetric efficiency | |
| 216. |
A Curtis turbine is |
| A. | A velocity compounded readtion turbine |
| B. | A pressure compounded reaction turbine |
| C. | A pure reaction turbine |
| D. | An impulse reaction turbine |
| E. | None of the above |
| Answer» B. A pressure compounded reaction turbine | |
| 217. |
Scavenging efficiency of a four stroke diesel engine is |
| A. | In the range 80 to 95 percent |
| B. | In the range 50 - 80 percent |
| C. | Below 50 percent |
| D. | Between 100% and 95% |
| E. | None of the above |
| Answer» E. None of the above | |
| 218. |
For minimum work in multistage compression, the work done on |
| A. | First stage should be least |
| B. | Last stage should be least |
| C. | All stage should be equal |
| D. | There is no such consideration |
| E. | None of the above |
| Answer» D. There is no such consideration | |
| 219. |
Cetane number of diesel generally used in India is in the range |
| A. | 55 to 65 |
| B. | 40 to 55 |
| C. | 20 to 25 |
| D. | 15 to 20 |
| E. | 10 to 15 |
| Answer» C. 20 to 25 | |
| 220. |
Absolute pressure is |
| A. | Gauge pressure |
| B. | Gauge pressure + 1.03 kg/cm2 |
| C. | Gauge pressure-atmospheric pressure |
| D. | Gauge pressure + atmospheric pressure |
| E. | None of the above |
| Answer» E. None of the above | |
| 221. |
For same heat input and same compression ratio |
| A. | Otto cycle and Diesel cycle are equally efficient |
| B. | Otto cycle is less efficient than Diesel cycle |
| C. | Otto cycle is more efficient than Diesel cycle |
| D. | Efficiency depends mainly on working substance |
| E. | None of the above |
| Answer» D. Efficiency depends mainly on working substance | |
| 222. |
The volumetric efficiency of a well adjusted engine at full load may be |
| A. | 40 to 55 percent |
| B. | 10 to 30 percent |
| C. | 75 to 95 percent |
| D. | 50 to 65 percent |
| E. | 30 to 45 percent |
| Answer» D. 50 to 65 percent | |
| 223. |
Which locomotives has the highest unbalanced forces? |
| A. | Electric locomotives |
| B. | Steam locomotives |
| C. | Carbon dioxide |
| D. | Diesel locomotives |
| Answer» C. Carbon dioxide | |
| 224. |
The maximum amount of dissociation occurs in the burnt gases of a |
| A. | Carbon dioxide |
| B. | lean mixture |
| C. | chernically correct mixture |
| D. | rich fuel mixture |
| E. | weak fuel mixture |
| Answer» D. rich fuel mixture | |
| 225. |
The bottom ring on the piston is known as |
| A. | Oil ring |
| B. | Scrapper ring |
| C. | Compression ring |
| D. | Groove ring |
| E. | Any of the above |
| Answer» B. Scrapper ring | |
| 226. |
For the same maximum pressure and heat input the least efficient cycle is |
| A. | Diesel cycle |
| B. | Otto cycle |
| C. | Weight of engine |
| D. | Brayton |
| Answer» D. Brayton | |
| 227. |
In a Carnot cycle the algebraic sum of the entropy changes for the cycle is |
| A. | Zero |
| B. | Either positive or negative |
| C. | Negative |
| D. | Depends on the properties of working substance |
| E. | Positive |
| Answer» B. Either positive or negative | |
| 228. |
Samples of exhaust gases from following engines have been collected |
| A. | Diesel engine |
| B. | Gas engine |
| C. | 600;1 |
| D. | Petrol engine |
| E. | Jet propulsion unit |
| Answer» F. | |
| 229. |
The boilers using lignite as fuel do not use |
| A. | Horizontal burner, pulverized fuel |
| B. | Travelling grate stoker |
| C. | U-flame pulverized fuel burner |
| D. | Speader stoker |
| E. | Underfeed stoker |
| Answer» F. | |
| 230. |
In Ambassador car, the engine is |
| A. | Multi-cylinder type |
| B. | V-type |
| C. | Air cooled and reciprocating engines |
| D. | Horizontal |
| E. | Constant speed type |
| Answer» B. V-type | |
| 231. |
In a compression ignition engine squish is |
| A. | Created at the beginning of suction stroke |
| B. | Created at the end of suction stroke |
| C. | Created during combustion |
| D. | Created towards the end of compression stroke |
| E. | None of the above |
| Answer» E. None of the above | |
| 232. |
A turbo-charger is used |
| A. | In gas turbines for compression of air |
| B. | For supercharging reciprocating engine |
| C. | In jet propulsion units |
| D. | In rockets for producing air fuel mixture |
| E. | None of the above |
| Answer» C. In jet propulsion units | |
| 233. |
Dehydration is the process of removal of |
| A. | hydrogen from water |
| B. | hydrogen from hydrocarbon |
| C. | moisture from anything that is wet |
| D. | hydrogen from alcohols |
| E. | addition of water vapour to a substance |
| Answer» D. hydrogen from alcohols | |
| 234. |
Dehydration means |
| A. | Removing hydrogen from a mixture |
| B. | Removing hydrogen from a hydrocarbon |
| C. | Removing water from any matter |
| D. | Removing hydrides from any matter |
| E. | Any of the above |
| Answer» D. Removing hydrides from any matter | |
| 235. |
Which is the external loss in a steam turbine? |
| A. | Blade friction losses |
| B. | Nozzle losses |
| C. | Disc friction losses |
| D. | Back pressure losses |
| E. | Gland leakage losses |
| Answer» E. Gland leakage losses | |
| 236. |
In compression ignition engines swirl is |
| A. | Circular motion imparted to gases after combustion |
| B. | Circular motion imparted to suction air |
| C. | Radial motion imparted to fuel air mixture |
| D. | Directional movement of fuel spray |
| E. | None of the above |
| Answer» C. Radial motion imparted to fuel air mixture | |
| 237. |
A four wheel drive automobile has |
| A. | Four stroke engine |
| B. | Air cooled engine |
| C. | Four flywheels |
| D. | Four cylinders |
| E. | Two differentials |
| Answer» F. | |
| 238. |
The work done in compressing 1 kg of air in compression will be least when the value of index is |
| A. | 1.1 |
| B. | 1 |
| C. | 1.2 |
| D. | 1.41 |
| E. | 1.5 |
| Answer» C. 1.2 | |
| 239. |
If petrol is supplied to a diesel engine |
| A. | The engine will run at high speeds |
| B. | The engine will run with excessive vibrations |
| C. | The engine will explode |
| D. | The engine will run with high knocking |
| E. | The engine will not run |
| Answer» E. The engine will not run | |
| 240. |
The function of a receiver in compressor installations is |
| A. | To collect compressed air |
| B. | To dempen pulsations or pressure waves incompressor discharge |
| C. | To reduce temperature of compressed air |
| D. | To reduce moisture content of compressed air |
| E. | None of the above |
| Answer» C. To reduce temperature of compressed air | |
| 241. |
Which of the following has the lowest pressure in a petrol engine? |
| A. | Gases during power stroke |
| B. | Mixture at the end of compression stroke |
| C. | Mixture at the beginning of suction stroke |
| D. | Mixture at the end of suction stroke |
| E. | Gases during exhaust stroke |
| Answer» E. Gases during exhaust stroke | |
| 242. |
During throttle governing of steam engines |
| A. | Cut off of the engine cylinder changes according to the load |
| B. | Pressure of steam supplied does not change with the load |
| C. | Thermal efficiency of the engine reduces |
| D. | Mechanical efficiency of the engine increases |
| E. | None of the above |
| Answer» D. Mechanical efficiency of the engine increases | |
| 243. |
Which of the following acts as a step up transformer in the ignition circuit of a petrol engine? |
| A. | Battery |
| B. | Coil |
| C. | Plug |
| D. | Distributor |
| E. | Magneto |
| Answer» B. Coil | |
| 244. |
In a compression ignition engine the fuel consumption will increase if the back (exhaust) pressure is |
| A. | Decreased |
| B. | Increased |
| C. | Does not have any effect |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» C. Does not have any effect | |
| 245. |
The efficiency of jet engine is higher at |
| A. | Lower altitudes |
| B. | Higher altitude |
| C. | Low speeds |
| D. | High speeds |
| E. | None of the above |
| Answer» C. Low speeds | |
| 246. |
A sample of water having pH value of 7 is |
| A. | Acidic |
| B. | Alkaline |
| C. | Neutral |
| D. | None of the above |
| Answer» D. None of the above | |
| 247. |
For the same maximum pressure and heat input, the most efficient cycle is |
| A. | Diesel |
| B. | 5 to 10 percent |
| C. | Brayton |
| D. | Otto |
| E. | Dual |
| Answer» D. Otto | |
| 248. |
The discharge of hydrocarbons from an automobile exhaust is minimum when the vehicle is |
| A. | Decelerating |
| B. | Cruising at high speeds |
| C. | Cruising at low speeds |
| D. | Accelerating |
| E. | Idling |
| Answer» F. | |
| 249. |
Thermal efficiency of a spark ignition engine at full load usually is in the range |
| A. | 30 to 35 percent |
| B. | 50 to 70 percent |
| C. | 70 to 90 percent |
| D. | 10 to 25 percent |
| E. | 5 to 10 percent |
| Answer» B. 50 to 70 percent | |
| 250. |
In an analysis report of a sample of coal, the percentage of one of the constituents is specified as 2.5%. This constituent could be |
| A. | Carbon steel |
| B. | Ash |
| C. | Moisture |
| D. | Sulphur |
| E. | None of the above |
| Answer» E. None of the above | |