McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 201. |
A radiation pyrometer is used for temperatures |
| A. | Upto 100?C |
| B. | Below 100?C |
| C. | Above 500?C |
| D. | 250 - 500?C |
| E. | 100 - 250?C |
| Answer» C. Above 500?C | |
| 202. |
The processes in a Rankine cycle are |
| A. | Two isothermal and two isentropic |
| B. | Two isothermal and two polytropic |
| C. | Two isothermal and two isobaric |
| D. | One constant pressure, one constant volume and two polytropic |
| E. | None of the above |
| Answer» E. None of the above | |
| 203. |
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» B. To dempen pulsations or pressure waves incompressor discharge | |
| 204. |
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» D. Sulphur | |
| 205. |
Apart from reducing friction and cooling the surfaces, the function of lubricant in I.C. engines is |
| A. | To improve thermal efficiency |
| B. | To clean the surfaces by carrying away the carbon and metal particles cansed by wear |
| C. | To reduce noise |
| D. | To reduce vibrations |
| E. | None of the above |
| Answer» B. To clean the surfaces by carrying away the carbon and metal particles cansed by wear | |
| 206. |
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» C. Thermal efficiency of the engine reduces | |
| 207. |
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» B. Higher altitude | |
| 208. |
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» B. Increased | |
| 209. |
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» D. The engine will run with high knocking | |
| 210. |
A sample of water having pH value of 7 is |
| A. | Acidic |
| B. | Alkaline |
| C. | Neutral |
| E. | None of the above |
| Answer» C. Neutral | |
| 211. |
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» D. Mixture at the end of suction stroke | |
| 212. |
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» E. Idling | |
| 213. |
Load curve is the plot of |
| A. | Load versus generatng capacity |
| B. | Load versus current |
| C. | Load versus time |
| D. | Load versus cost of power |
| E. | None of the above |
| Answer» C. Load versus time | |
| 214. |
With reference to a safety valve the blow down pressure is the pressure at which |
| A. | Valve opens |
| B. | Valve closes after opening |
| C. | Valve opens initially |
| D. | Valve spring pressure is adjusted |
| E. | None of the above |
| Answer» B. Valve closes after opening | |
| 215. |
A four wheel drive automobile has |
| A. | Four stroke engine |
| B. | Air cooled engine |
| C. | Four flywheels |
| D. | Four cylinders |
| E. | Two differentials |
| Answer» E. Two differentials | |
| 216. |
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» B. 1 | |
| 217. |
Separators are generally used in air compressor installations |
| A. | Between after cooler and receiver |
| B. | Before first stage suction |
| C. | Before intercooler |
| D. | After intercooler |
| E. | None of the above |
| Answer» A. Between after cooler and receiver | |
| 218. |
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» C. Brayton | |
| 219. |
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» B. Circular motion imparted to suction air | |
| 220. |
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» A. Battery | |
| 221. |
Tidal power is the power generated from |
| A. | Raw sea water |
| B. | Waves of the ocean |
| C. | Rise and fall tides |
| D. | Thermal energy of ocean water |
| E. | Chemicals in sea water |
| Answer» C. Rise and fall tides | |
| 222. |
Percentage improvement in power in case of a four stroke diesel engine with the help of a supercharger may be expected in the range |
| A. | 25 |
| B. | 35 |
| C. | 75 |
| D. | 50 |
| E. | 100 |
| Answer» C. 75 | |
| 223. |
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» A. 30 to 35 percent | |
| 224. |
A Lungistrom turbine is |
| A. | Impulse turbine |
| B. | Reaction turbine |
| C. | Outward radial flow turbine |
| D. | Inward flow impulse reaction turbine |
| E. | None of the above |
| Answer» C. Outward radial flow turbine | |
| 225. |
Diesel engine has air fuel ratio of 30 ; 1 during idling. A petrol engine can also work on such mixture provided |
| A. | Ignition timing is changed |
| B. | Carburettor is modified |
| C. | Dannot run as it is impossible |
| D. | Runs smoothly at lower speeds only |
| E. | Engine is suitably modified |
| Answer» C. Dannot run as it is impossible | |
| 226. |
The amount of exhaust gases in clearance space left after exhaust stroke, varies with |
| A. | Clearance volume |
| B. | Carbon dioxide |
| C. | air-fuel ratio of charger |
| D. | Speed and load of the engine |
| E. | Bore and length of cylinder |
| Answer» D. Speed and load of the engine | |
| 227. |
Out of the following diesel engine the minimum air consumption per B.H.P. will be in |
| A. | 50% |
| B. | 4 stroke, air injection |
| C. | 2 stroke, air injection |
| D. | 2 stroke, mech, injection, pump, scavenging |
| E. | 4 stroke, mech, injection |
| Answer» E. 4 stroke, mech, injection | |
| 228. |
Enthalpy of a substance is defined as |
| A. | The sum of internal energy and the work done in forcing unit mass of substance into an enclosure at the constant pressure at which the substance exists |
| B. | Sum of sensible heat + latent heat of substance |
| C. | Total heat content of substance above zero degree centigrade |
| D. | Sensible heat of water + work done in forcing unit mass of substance into an enclosure at constant pressure at which the substance exists |
| E. | None of the above |
| Answer» C. Total heat content of substance above zero degree centigrade | |
| 229. |
Endurance test for I.C. engines is conducted for |
| A. | 1000 hours |
| B. | 200 hours |
| C. | 500 hours |
| D. | 400 hours |
| E. | 100 hours |
| Answer» C. 500 hours | |
| 230. |
A system having connected load of 100 kW, peak load of 80 kW, base load of 20 kW and average load of 40 kW will have a load factor of |
| A. | 60% |
| B. | 40% |
| C. | 75% |
| D. | 80% |
| E. | 50% |
| Answer» E. 50% | |
| 231. |
The value of reheat factor in case of steam turbines is usually |
| A. | 1.25 to 1.50 |
| B. | 1.02 to 1.06 |
| C. | 1.10 to 1.16 |
| D. | 1.75 to 2.50 |
| E. | 0.9 to 0.99 |
| Answer» B. 1.02 to 1.06 | |
| 232. |
A fuel of octane rating 85 matches the antiknock qualities of mixture consisting of |
| A. | 85% heptane + 15% octane |
| B. | 85% octane + 15% heptane |
| C. | 85% petrol + 15% diesel |
| D. | 85% benzene + 15% methyl alcohol |
| E. | 15% petrol + 85% diesel |
| Answer» B. 85% octane + 15% heptane | |
| 233. |
A Wankel engine combines the advantages of |
| A. | SI and CI engines |
| B. | Carburction and fuel injection |
| C. | Air cooled and reciprocating engines |
| D. | Rotory and reciprocating engines |
| E. | Axial flow and centrifugal compression |
| Answer» D. Rotory and reciprocating engines | |
| 234. |
Willian's line is relevant to |
| A. | Throttle controlled trbine |
| B. | Nozzle controlled turbines |
| C. | Impulse turbines |
| D. | Reaction turbines |
| E. | None of the above |
| Answer» A. Throttle controlled trbine | |
| 235. |
Starting motor in automobiles is generally |
| A. | Induction motor |
| B. | Synchronous motor |
| C. | Squirrel cage motor |
| D. | Shunt motor |
| E. | Series motor |
| Answer» E. Series motor | |
| 236. |
Three states of matter are distinguished with repect to molecules by |
| A. | Characteristics of the motion of molecules |
| B. | The number |
| C. | Energy of molecules |
| D. | The atoms in molecules |
| E. | The orientation of molecules |
| Answer» A. Characteristics of the motion of molecules | |
| 237. |
Tenacity is the property of materials in which they |
| A. | Resist indentation |
| B. | Resist rupture |
| C. | Resist shearing |
| D. | Resist deformation |
| E. | None of the above |
| Answer» B. Resist rupture | |
| 238. |
The horse power of engine for a ship is of the order to |
| A. | 10,000 to 40,000 |
| B. | 50 to 100 |
| C. | 1000 to 5000 |
| D. | 100 to 500 |
| E. | 500 to 1000 |
| Answer» A. 10,000 to 40,000 | |
| 239. |
As the steam flows in a subsonic nozzle, in which the cross-section is decreasing in the direction of flow |
| A. | The velocity will decrease in the direction of flow |
| B. | The pressure will increase in the direction of flow |
| C. | The velocity will decrease while pressure will decrease in the direction of flow |
| D. | The velocity will increase while pressure will decrease in the direction of flow |
| E. | None of the above |
| Answer» D. The velocity will increase while pressure will decrease in the direction of flow | |
| 240. |
White smoke from a diesel engine can be expected during |
| A. | Start up or idling |
| B. | High speed operation |
| C. | High load operation |
| D. | All of the above |
| E. | None of the above |
| Answer» A. Start up or idling | |
| 241. |
Total sulphur content in a diesel fuel oil must not exceed |
| A. | 0.10% |
| B. | 0.01% |
| C. | 0.05% |
| D. | 0.50% |
| E. | 1% |
| Answer» D. 0.50% | |
| 242. |
Air consumption of a four-stroke diesel engine per rated BHP/hr will be |
| A. | 20 kg |
| B. | 1 kg |
| C. | 5 - 7 kg |
| D. | 10 - 14 kg |
| E. | 15 kg |
| Answer» C. 5 - 7 kg | |
| 243. |
In spark ignition engines the knocking tendency decreases |
| A. | As compression ratio is reduced |
| B. | By controlling air/fuel mixture |
| C. | By controlling ignition timing |
| D. | By controlling exhaust temperatures |
| E. | None of the above |
| Answer» A. As compression ratio is reduced | |
| 244. |
Water and sediments in a diesel fuel oil must not exceed. |
| A. | 0.50% |
| B. | 0.01% |
| C. | 1% |
| D. | 0.10% |
| E. | 0.05% |
| Answer» E. 0.05% | |
| 245. |
Rankine cycle efficiency for fixed steam temperature of any volume upto critical temperature will be maximum for steam pressure of |
| A. | 250 kg/cm2 |
| B. | 100 kg/cm2 |
| C. | 200 kg/cm2 |
| D. | Critical pressure |
| E. | 203.5 kg/cm2 |
| Answer» D. Critical pressure | |
| 246. |
A certain gas occupies 2 cu-m at a temperature of 400?C. It receives heat at constant pressure till its temperature is doubled. The change in volume would be |
| A. | 0.19 cu-m |
| B. | 3.8 cu-m |
| C. | 0.038 cu-m |
| D. | 0.019 cu-m |
| E. | 3.188 cu-m |
| Answer» E. 3.188 cu-m | |
| 247. |
If the power factor of an electrical system is unity, it means |
| A. | Efficiency is least |
| B. | Entire power is consumed in reactive power |
| C. | Entire power pulls the load |
| D. | Equipment is running properly |
| E. | Magnetism generated within the equipment is negligible |
| Answer» C. Entire power pulls the load | |
| 248. |
A fixed quantity of heat is to be added to a system under specific conditions. The process in which the entropy change will be maximum is |
| A. | Constant pressure process |
| B. | Constant volume process |
| C. | Constant temperature process |
| D. | Isentropic process |
| E. | None of the above |
| Answer» C. Constant temperature process | |
| 249. |
Air standard efficiency of an I.C. engine depends on |
| A. | Compression ratio |
| B. | Speed of operation |
| C. | Fuel used |
| D. | Torque |
| E. | All of the above |
| Answer» A. Compression ratio | |
| 250. |
Which of the following is false statement? |
| A. | Fuel consumption of engine increases if silencer is choked |
| B. | Fuel consumption of engines decreases if air filter is choked |
| C. | Fuel consumption increases if exhaust valve is burnt |
| D. | Fuel consumption increases if lean mixture is supplied |
| E. | All of the above |
| Answer» D. Fuel consumption increases if lean mixture is supplied | |
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