MCQOPTIONS
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MCQOPTIONS
This section includes 286 Mcqs, each offering curated multiple-choice questions to sharpen your GATE (Mechanical Engineering) knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Plutonium (Pu239) is produced |
| A. | artificially |
| B. | by fission of Th232 |
| C. | when U238 is irradiated by neutrons |
| D. | as basic raw material |
| Answer» D. as basic raw material | |
| 202. |
Ordinary water is sometimes used as moderator when enriched uranium is used as a fuel in nuclear power plants. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 203. |
The higher combustion chamber wall temperature in compression ignition engines will __________ knocking tendency. |
| A. | increase |
| B. | reduce |
| C. | not effect |
| D. | None of these |
| Answer» C. not effect | |
| 204. |
The delay period in compression ignition engines depends upon |
| A. | temperature and pressure in the cylinder at the time of injection |
| B. | nature of the fuel mixture strength |
| C. | relative velocity between the fuel injection and air turbulence pressure of residual gases |
| D. | all of the above |
| Answer» E. | |
| 205. |
The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called |
| A. | mechanical efficiency |
| B. | overall efficiency |
| C. | volumetric efficiency |
| D. | relative efficiency |
| Answer» D. relative efficiency | |
| 206. |
The combustion in compression ignition engines is |
| A. | homogeneous |
| B. | hetrogeneous |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» C. both (a) and (b) | |
| 207. |
A higher compression ratio causes |
| A. | pre-ignition |
| B. | increase in detonation |
| C. | an acceleration in the rate of combustion |
| D. | any one of these |
| Answer» E. | |
| 208. |
The ratio of the brake power to the indicated power is called |
| A. | mechanical efficiency |
| B. | overall efficiency |
| C. | indicated thermal efficiency |
| D. | volumetric efficiency |
| Answer» B. overall efficiency | |
| 209. |
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. | |
| 210. |
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 |
| C. | Can't say |
| D. | None of these |
| Answer» B. Incorrect | |
| 211. |
The pressure at the end of compression, in diesel engines, is approximately |
| A. | 10 bar |
| B. | 20 bar |
| C. | 25 bar |
| D. | 35 bar |
| Answer» E. | |
| 212. |
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 | |
| 213. |
The sparking in a petrol engine increases pressure and temperature of the products of combustion, but the volume remains constant. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 214. |
In qualitative governing, the quantity of fuel is varied to suit the load on the engine and the total charge of air is altered. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 215. |
The predominent isotope of the naturally occuring element is |
| A. | U235 |
| B. | U238 |
| C. | Pu233 |
| D. | Pu239 |
| Answer» C. Pu233 | |
| 216. |
A diesel engine, during suction stroke, draws |
| A. | air only |
| B. | diesel only |
| C. | a mixture of diesel and air |
| D. | None of these |
| Answer» B. diesel only | |
| 217. |
The probability of knocking in diesel engines is increased by |
| A. | high self ignition temperature |
| B. | low volatility |
| C. | higher viscosity |
| D. | all of these |
| Answer» E. | |
| 218. |
The unit million electron volts (Mev) is commonly used to measure the nuclear energy. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 219. |
The knocking in spark ignition engines can be reduced by |
| A. | retarding the spark |
| B. | increasing the engine speed |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» D. none of these | |
| 220. |
The cylinder of a gas engine is made __________ than that of the petrol engine. |
| A. | smaller |
| B. | larger |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 221. |
Each fission of U235 produces on the average __________ fast neutrons as a product of reaction. |
| A. | 2.46 |
| B. | 24.6 |
| C. | 246 |
| D. | 2460 |
| Answer» B. 24.6 | |
| 222. |
The mean effective pressure of a diesel engine having fixed compression ratio will __________ if cut off ratio decreases. |
| A. | increase |
| B. | decrease |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 223. |
The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the |
| A. | jet area is automatically varied depending on the suction |
| B. | the flow from the main jet is diverted to the compensating jet with increase in speed |
| C. | the diameter of the jet is constant and the discharge coefficient is invariant |
| D. | flow is produced due to the static head in the float chamber |
| Answer» E. | |
| 224. |
The injection pressure in a diesel engine is about |
| A. | 10 bar |
| B. | 100 bar |
| C. | 150 bar |
| D. | 500 bar |
| Answer» C. 150 bar | |
| 225. |
The nuclear power station at Tarapur has the reactor of the __________ type. |
| A. | pressurized water |
| B. | boiling water |
| C. | gas cooled |
| D. | liquid metal cooled |
| Answer» C. gas cooled | |
| 226. |
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 | |
| 227. |
Iso-octane (C8H18) has octane number of |
| A. | 0 |
| B. | 50 |
| C. | 100 |
| D. | 120 |
| Answer» D. 120 | |
| 228. |
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. | |
| 229. |
The pre-ignition occurs before the spark is produced whereas detonation develops after the introduction of spark. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» B. Disagree | |
| 230. |
A carburettor is used to supply |
| A. | petrol, air and lubricating oil |
| B. | air and diesel |
| C. | petrol and lubricating oil |
| D. | petrol and air |
| Answer» E. | |
| 231. |
The increase of cooling water temperature in petrol engine will __________ the knocking tendency. |
| A. | not effect |
| B. | decrease |
| C. | increase |
| D. | None of these |
| Answer» D. None of these | |
| 232. |
The self ignition temperature of petrol is __________ as compared to diesel oil. |
| A. | same |
| B. | lower |
| C. | higher |
| D. | None of these |
| Answer» D. None of these | |
| 233. |
The pressure inside the cylinder is __________ the atmospheric pressure during the exhaust stroke. |
| A. | equal to |
| B. | below |
| C. | above |
| D. | None of these |
| Answer» D. None of these | |
| 234. |
A diesel engine has |
| A. | one valve |
| B. | two valves |
| C. | three valves |
| D. | four valves |
| Answer» D. four valves | |
| 235. |
The presence of reflector in nuclear power plants results in |
| A. | increased production of neutrons |
| B. | complete absorption of neutrons |
| C. | controlled production of neutrons |
| D. | decreased leakage of neutrons |
| Answer» E. | |
| 236. |
The efficiency of a nuclear power plant in comparison to conventional and nuclear consideration is |
| A. | higher cost of nuclear fuel |
| B. | high initial cost |
| C. | high heat rejection in condenser |
| D. | lower temperature and pressure condi-tions |
| Answer» E. | |
| 237. |
The most practical fuel for a thermo-nuclear reactor, both from econocical and nuclear consideration is |
| A. | plutonium |
| B. | uranium |
| C. | deuterium |
| D. | thorium |
| Answer» D. thorium | |
| 238. |
Pressurised water reactor isdesigned |
| A. | for boiling pi water in the core |
| B. | to use liquid sodium metal as coolant |
| C. | to use intermediate coolant |
| D. | to prevent the water coolant from boiling in the core |
| Answer» E. | |
| 239. |
Half life of a radioactive isotope corresponds to the time required for half of the following to decay |
| A. | electrons |
| B. | protons |
| C. | neutrons |
| D. | atom |
| Answer» E. | |
| 240. |
A fast breeder reactor uses |
| A. | 90% U-235 |
| B. | U-238 |
| C. | U-235 |
| D. | Pu-239 |
| Answer» B. U-238 | |
| 241. |
A fast breeder reactor uses following as fuel |
| A. | enriched uranium |
| B. | plutonium |
| C. | thorium |
| D. | U235 |
| Answer» E. | |
| 242. |
Each fission of U235 produces following number of fast neutrons per fission |
| A. | 1 neutron |
| B. | 1 — neutrons |
| C. | 1 - 2 neutrons |
| D. | 2 — neutrons |
| Answer» E. | |
| 243. |
In a fission process, maximum %age of energy is released as |
| A. | kinetic energy of neutrons |
| B. | kinetic energy of fission products |
| C. | instantaneous release of gamma rays |
| D. | gradual readioactive decay of fission products |
| Answer» C. instantaneous release of gamma rays | |
| 244. |
Effective moderators are those materials which contain |
| A. | light weight atoms |
| B. | heavy weight atoms |
| C. | critical atoms |
| D. | zero weight atoms |
| Answer» B. heavy weight atoms | |
| 245. |
In triggering fission, the following types of neutrons are desirable |
| A. | fast moving |
| B. | slow moving |
| C. | critical neutrons |
| D. | neutrons at reset |
| Answer» C. critical neutrons | |
| 246. |
Solid- fuel for nuclear reactions may be fabricated into various small shapes such as |
| A. | plates |
| B. | pallets |
| C. | pins |
| D. | any one of the above |
| Answer» E. | |
| 247. |
Supertheated steam is generated in following reactor |
| A. | boiling water |
| B. | gas cooled |
| C. | pressurised water |
| D. | all of the above |
| Answer» C. pressurised water | |
| 248. |
Reactors designed for propulsion applications are designed for |
| A. | natural uranium |
| B. | enriched uranium |
| C. | pure uranium |
| D. | any type of uranium |
| Answer» C. pure uranium | |
| 249. |
When a reactor becomes critical, then the production of neutrons is |
| A. | infinite |
| B. | zero |
| C. | exactly balanced by the loss of neutrons through leakage |
| D. | initiated |
| Answer» D. initiated | |
| 250. |
The size of the reactor is said to be critical when |
| A. | chain reaction can be initiated |
| B. | it becomes uncontrollable |
| C. | it explodes |
| D. | it produces no power |
| Answer» B. it becomes uncontrollable | |