MCQOPTIONS
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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.
| 151. |
Injection system in which the pump and the injector nozzle is combined in one housing is known as |
| A. | common rail system |
| B. | distributor system |
| C. | unit injector system |
| D. | individual pump and nozzle system |
| Answer» D. individual pump and nozzle system | |
| 152. |
Charge pressure at the inlet port of a two-stroke engine is |
| A. | 20 bar |
| B. | vacuum |
| C. | atmospheric |
| D. | higher than atmospheric |
| Answer» E. | |
| 153. |
Fuel-air ratio affects maximum power output of the engine due to |
| A. | higher specific heats |
| B. | chemical equilibrium losses |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 154. |
For a given compression ratio the work output of Otto cycle is |
| A. | increases with Increase in r |
| B. | decreases with increase in r |
| C. | is not affected |
| D. | none of the above |
| Answer» B. decreases with increase in r | |
| 155. |
with increase in compression ratio flame speed |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | none of the above |
| Answer» B. decreases | |
| 156. |
For peak lead operation, the spark advance |
| A. | must be decreased |
| B. | must be increased |
| C. | need not be altered |
| D. | none of the above |
| Answer» B. must be increased | |
| 157. |
In CI engines the delay period is affected by |
| A. | compression ratio |
| B. | engine speed |
| C. | output |
| D. | all of the above |
| Answer» E. | |
| 158. |
Why are lead compounds added in petrol? |
| A. | Reduce knocking |
| B. | Reduce HC emission |
| C. | Reduce exhaust temperature |
| D. | Increase power output |
| Answer» C. Reduce exhaust temperature | |
| 159. |
Compression ratio of LC. Engines is |
| A. | the ratio of volumes of air in cylinder before compression stroke and after compression stroke |
| B. | volume displaced by piston per stroke and clearance volume in cylinder |
| C. | ratio of pressure after compression and before compression |
| D. | swept volume/cylinder volume |
| Answer» B. volume displaced by piston per stroke and clearance volume in cylinder | |
| 160. |
Battery ignition system |
| A. | occupies more space |
| B. | has more maintenance problem |
| C. | is commonly employed in four wheelers |
| D. | all of the above |
| Answer» E. | |
| 161. |
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» B. 2N | |
| 162. |
Which stage of vehicle emission norms presently applicable in India in Internal CombustionEngine? |
| A. | Bharat Stage V |
| B. | Bharat Stage IV |
| C. | Bharat Stage III |
| D. | Bharat Stage II |
| Answer» C. Bharat Stage III | |
| 163. |
In CI engines knocking tendency increases with |
| A. | increase in compression ratio |
| B. | increasing inlet temperature of air |
| C. | decrease in compression ratio |
| D. | increasing coolant water temperature |
| Answer» D. increasing coolant water temperature | |
| 164. |
Venturi in the carburetor results in |
| A. | decrease of air velocity |
| B. | increase of air velocity |
| C. | decrease of fuel flow |
| D. | increase of manifold vacuum |
| Answer» C. decrease of fuel flow | |
| 165. |
Economizer is used to provide enriched mixture during |
| A. | Starling |
| B. | idling |
| C. | cruising |
| D. | full throttle operation |
| Answer» E. | |
| 166. |
When the throttle is suddenly opened, the mixture of the simple carburetor tends tobecome |
| A. | rich |
| B. | lean |
| C. | stoichiometric |
| D. | not affected |
| Answer» C. stoichiometric | |
| 167. |
Which is more viscous lib oil |
| A. | SEA 30 |
| B. | SAE 40 |
| C. | SAE 50 |
| D. | SAE 80. |
| Answer» E. | |
| 168. |
Vacuum advance mechanism shifts the ignition point under |
| A. | no load operation |
| B. | full load operation |
| C. | part load operation |
| D. | under sudden acceleration |
| Answer» D. under sudden acceleration | |
| 169. |
For CI engine fuels most preferred are |
| A. | napthenes |
| B. | paraffins |
| C. | olefins |
| D. | aromatics |
| Answer» C. olefins | |
| 170. |
In SI engines flame speed increases |
| A. | with turbulence |
| B. | with fuel-air ratio |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 171. |
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» C. N | |
| 172. |
The choke in an automobile meant for supplying |
| A. | lean mixture |
| B. | rich mixture |
| C. | stoichiometric mixture |
| D. | weak mixture |
| Answer» C. stoichiometric mixture | |
| 173. |
Friction that occurs between the layers of oil film is called |
| A. | viscous friction |
| B. | greasy friction |
| C. | dry friction |
| D. | boundary friction |
| Answer» B. greasy friction | |
| 174. |
With dissociation the exhaust gas temperature |
| A. | decreases |
| B. | increases |
| C. | no effect |
| D. | increases upto certain air-fuel ratio and then decreases |
| Answer» B. increases | |
| 175. |
EGR (Exhaust Gas Recirculation) system is employed for controlling emissions of: |
| A. | HC |
| B. | CO |
| C. | NOx |
| D. | HC and CO |
| Answer» D. HC and CO | |
| 176. |
Volumetric efficiency of supercharged engine is |
| A. | between 100 - 110% |
| B. | between 90 - 100% |
| C. | between 80 - 90% |
| D. | between 70 - 80% |
| Answer» B. between 90 - 100% | |
| 177. |
Fuel filters do not use generally |
| A. | oil |
| B. | paper |
| C. | cloth |
| D. | felt |
| Answer» C. cloth | |
| 178. |
the most important property of the lubricant is |
| A. | density |
| B. | viscosity |
| C. | thermal conductivity |
| D. | none of the above |
| Answer» C. thermal conductivity | |
| 179. |
Most commonly used lubrication system in automobiles is the |
| A. | splash system |
| B. | pressure system |
| C. | petrol system |
| D. | gravity system |
| Answer» C. petrol system | |
| 180. |
During which condition of the vehicle does NOx emission in SI engine will be lowest? |
| A. | Cruising |
| B. | Idling |
| C. | Accelerating |
| D. | Decelerating |
| Answer» C. Accelerating | |
| 181. |
Decreasing the cooling water temperature in SI engines the knocking tendency |
| A. | increases |
| B. | decreases |
| C. | not affected |
| D. | none of the above |
| Answer» C. not affected | |
| 182. |
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» C. 60% to 80% | |
| 183. |
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» B. pressurise the cooling water | |
| 184. |
The major contributor of Carbon monoxide is |
| A. | Motor vehicle |
| B. | Industrial processes |
| C. | Stationary fuel combustion |
| D. | None of the above |
| Answer» B. Industrial processes | |
| 185. |
The maximum pressure in the lubrication system is controlled by |
| A. | oil pump |
| B. | oil filter |
| C. | valve relief |
| D. | supply voltage |
| Answer» D. supply voltage | |
| 186. |
Compression loss in I.C engines occurs duto |
| A. | leaking piston rings |
| B. | use of thick head gasket |
| C. | clogged air-inlet slots |
| D. | all of the above. |
| Answer» E. | |
| 187. |
Increasing the compression ratio in SI engines the knocking tendency |
| A. | decreases |
| B. | increases |
| C. | not affected |
| D. | none of the above |
| Answer» C. not affected | |
| 188. |
With increase in speed the crank angle required for fame propagation |
| A. | increases |
| B. | decreases |
| C. | not affected |
| D. | none of the above |
| Answer» D. none of the above | |
| 189. |
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» D. none of the above | |
| 190. |
Detonation in SI engines occur due to |
| A. | pre ignition of the charge before the spark |
| B. | sudden ignition of the charge before the spark |
| C. | autoignition of the charge after the spark in struck |
| D. | none of the above |
| Answer» D. none of the above | |
| 191. |
The best method of measuring speed is by |
| A. | mechanical tachometer |
| B. | electrical tachometer |
| C. | magnetic pickup |
| D. | none of the above |
| Answer» D. none of the above | |
| 192. |
During starting petrol engines require |
| A. | stoichiometric mixture |
| B. | lean mixture |
| C. | rich mixture |
| D. | any air-fuel ratio is alright |
| Answer» D. any air-fuel ratio is alright | |
| 193. |
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» E. | |
| 194. |
In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then _________ is employed. |
| A. | uel pump |
| B. | njector |
| C. | arburettor |
| D. | one of these |
| Answer» D. one of these | |
| 195. |
A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed. |
| A. | alf |
| B. | ame |
| C. | ouble |
| D. | our times |
| Answer» D. our times | |
| 196. |
Polymerization is a chemical process in which molecules of a compound become |
| A. | arger |
| B. | lowed down |
| C. | maller |
| D. | iquid |
| Answer» B. lowed down | |
| 197. |
The cam shaft of a four stroke I.C. engine running at 1500 rpm will run at |
| A. | 500 rpm |
| B. | 50 rpm |
| C. | 000 rpm |
| D. | ny value independent of engine speed |
| Answer» C. 000 rpm | |
| 198. |
During idling, a petrol engine requires _________ mixture. |
| A. | ean |
| B. | ich |
| C. | hemically correct |
| D. | one of these |
| Answer» C. hemically correct | |
| 199. |
The magneto in an automobile is basically |
| A. | ransformer |
| B. | .C. generator |
| C. | apacitor |
| D. | agnetic circuit |
| Answer» C. apacitor | |
| 200. |
A spark plug gap is kept from |
| A. | .3 to 0.7 mm |
| B. | .2 to 0.8 mm |
| C. | .4 to 0.9 mm |
| D. | .6 to 1.0 mm |
| Answer» B. .2 to 0.8 mm | |