MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 454 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 volumetric efficiency for reciprocating air compressors is about? |
| A. | 10 to 40% |
| B. | 40 to 60% |
| C. | 60 to 70% |
| D. | 70 to 90% |
| Answer» E. | |
| 202. |
*/*_The blades of gas turbine are made of? |
| A. | High nickel alloy |
| B. | Stainless steel |
| C. | Carbon steel |
| D. | High alloy steel |
| Answer» B. Stainless steel | |
| 203. |
*/*_The type of rotary compressor used in gas turbines, is of? |
| A. | Centrifugal type |
| B. | Axial flow type |
| C. | Radial flow type |
| D. | None of these |
| Answer» C. Radial flow type | |
| 204. |
*/*_Clearance volume in actual reciprocating compressors is essential? |
| A. | To accommodate Valves in the cylinder head |
| B. | To provide cushioning effect |
| C. | To attain high volumetric efficiency |
| D. | To provide cushioning effect and also to avoid mechanical bang of piston with cylinder head |
| Answer» E. | |
| 205. |
*/*_Volumetric efficiency of air compressors is of the order of? |
| A. | 20 - 30% |
| B. | 40 - 50% |
| C. | 60 - 70% |
| D. | 70 - 90% |
| Answer» E. | |
| 206. |
*/*_Euler's equation is applicable for? |
| A. | Centrifugal compressor |
| B. | Axial compressor |
| C. | Pumps |
| D. | All of the above |
| Answer» E. | |
| 207. |
*/*_The most efficient method of compressing air is to compress it? |
| A. | Isothermally |
| B. | Adiabatically |
| C. | Isentropically |
| D. | Isochronically |
| Answer» B. Adiabatically | |
| 208. |
*/*_Axial flow compressor has the following advantage over centrifugal compressor? |
| A. | Larger air handling ability per unit frontal area |
| B. | Higher pressure ratio per stage |
| C. | Aerofoil blades are used |
| D. | Higher average velocities |
| Answer» B. Higher pressure ratio per stage | |
| 209. |
*/*_The effective power of gas turbines is increased by adding the following in compressor? |
| A. | Ammonia and water vapour |
| B. | Carbon dioxide |
| C. | Nitrogen |
| D. | Hydrogen |
| Answer» B. Carbon dioxide | |
| 210. |
*/*_Euler's equation can be used for? |
| A. | Radial flow compressors |
| B. | Axial flow compressors |
| C. | Pumps |
| D. | All of these |
| Answer» E. | |
| 211. |
*/*_In a centrifugal compressor, the ratio of the ________ to the blade velocity is called slip factor.? |
| A. | Inlet whirl velocity |
| B. | Outlet whirl velocity |
| C. | Inlet velocity of flow |
| D. | Outlet velocity of flow |
| Answer» E. | |
| 212. |
*/*_With the decrease in compression ratio, the volumetric efficiency? |
| A. | Does not change |
| B. | Increases |
| C. | Decreases |
| D. | First decrease and then increase |
| Answer» C. Decreases | |
| 213. |
*/*_Gas turbines use following type of air compressor? |
| A. | Centrifugal type |
| B. | Reciprocating type |
| C. | Lobe type |
| D. | Axial flow type |
| Answer» E. | |
| 214. |
*/*_For a two stage compressor, if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will? |
| A. | Increase |
| B. | Decrease |
| C. | Remain unaffected |
| D. | Other factors control it |
| Answer» B. Decrease | |
| 215. |
*/*_During peak load periods, the best method of controlling compressors is? |
| A. | Start-stop motor |
| B. | Constant speed unloader |
| C. | Relief valve |
| D. | Variable speed |
| Answer» C. Relief valve | |
| 216. |
*/*_The thrust on the rotor in a centrifugal compressor is produced by? |
| A. | Radial component |
| B. | Axial component |
| C. | Tangential component |
| D. | None of the above |
| Answer» C. Tangential component | |
| 217. |
*/*_Volumetric efficiency of a compressor decreases with ________ in compression ratio.? |
| A. | Decrease |
| B. | Increase |
| C. | Remain same |
| D. | Does not change |
| Answer» C. Remain same | |
| 218. |
*/*_Maximum work is done in compressing air when the compression is? |
| A. | Isothermal |
| B. | Adiabatic |
| C. | Polytropic |
| D. | None of the above |
| Answer» C. Polytropic | |
| 219. |
*/*_Gas turbine works on? |
| A. | Brayton or Atkinson cycle |
| B. | Carnot cycle |
| C. | Rankine cycle |
| D. | Ericsson cycle |
| Answer» B. Carnot cycle | |
| 220. |
*/*_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚ÇÅ = Intake pressure of air, p‚ÇÇ = Inter-cooler pressure, and p‚ÇÉ = Delivery pressure of air)? |
| A. | p‚ÇÇ = p‚ÇÅ √ó p‚ÇÉ |
| B. | p‚ÇÇ = p‚ÇÅ/p‚ÇÉ |
| C. | p‚ÇÇ = p‚ÇÅ √ó p‚ÇÇ |
| D. | p‚ÇÇ = p‚ÇÉ/p‚ÇÅ |
| Answer» D. p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö | |
| 221. |
*/*_The volume of air sucked by the compressor during its suction stroke is called? |
| A. | Free air delivery |
| B. | Compressor capacity |
| C. | Swept volume |
| D. | None of these |
| Answer» D. None of these | |
| 222. |
*/*_In a jet engine, the air-fuel ratio is? |
| A. | 30:1 |
| B. | 40:1 |
| C. | 50:1 |
| D. | 60:1 |
| Answer» E. | |
| 223. |
*/*_Gas turbine cycle with regenerator? |
| A. | Increases thermal efficiency |
| B. | Allows high compression ratio |
| C. | Decreases heat loss is exhaust |
| D. | Allows operation at very high altitudes |
| Answer» B. Allows high compression ratio | |
| 224. |
*/*_The overall thermal efficiency of an ideal gas turbine plant is (where r = Pressure ratio)? |
| A. | r …£-1 |
| B. | 1 - r …£-1 |
| C. | 1 - (1/r) …£-1/…£ |
| D. | 1 - (1/r) …£/…£-1 |
| Answer» D. 1 - (1/r) ‚Ķ¬£/‚Ķ¬£-1 | |
| 225. |
*/*_Isothermal compression though most efficient, but is not practicable because? |
| A. | It requires very big cylinder |
| B. | It does not increase pressure much |
| C. | It is impossible in practice |
| D. | Compressor has to run at very slow speed to achieve it |
| Answer» E. | |
| 226. |
*/*_In a double acting compressor, the air is compressed? |
| A. | In one cylinder |
| B. | In two cylinders |
| C. | In a single cylinder on both sides of the piston |
| D. | In two cylinders on both sides of the piston |
| Answer» D. In two cylinders on both sides of the piston | |
| 227. |
*/*_In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of? |
| A. | Vacuum |
| B. | Atmospheric air |
| C. | Compressed air |
| D. | Oxygen alone |
| Answer» D. Oxygen alone | |
| 228. |
*/*_Ratio of indicated H.P. and brake H.P. is known as? |
| A. | Mechanical efficiency |
| B. | Volumetric efficiency |
| C. | Isothermal efficiency |
| D. | Adiabatic efficiency |
| Answer» B. Volumetric efficiency | |
| 229. |
*/*_To avoid moisture troubles, the compressed air main line should? |
| A. | Rise gradually towards the point of use |
| B. | Drop gradually towards the point of use |
| C. | Be laid vertically |
| D. | Be laid exactly horizontally |
| Answer» C. Be laid vertically | |
| 230. |
*/*_The net work input required for compressor with increase in clearance volume? |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | Increases/decreases depending on compressor capacity |
| Answer» D. Increases/decreases depending on compressor capacity | |
| 231. |
*/*_Reheating in a multistage expansion gas turbine ________ compressor work.? |
| A. | Has no effect on |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» C. Increases | |
| 232. |
*/*_The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called? |
| A. | Slip factor |
| B. | Velocity factor |
| C. | Velocity coefficient |
| D. | None of the above |
| Answer» B. Velocity factor | |
| 233. |
*/*_Reheating in gas turbine results in? |
| A. | Increase of work ratio |
| B. | Decrease of thermal efficiency |
| C. | Decrease of work ratio |
| D. | Both (A) and (B) above |
| Answer» E. | |
| 234. |
*/*_Producer gas is produced by? |
| A. | Carbonisation of coal |
| B. | Passing steam over incandescent coke |
| C. | Passing air and a large amount of steam over waste coal at about 65°C |
| D. | Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast |
| Answer» E. | |
| 235. |
*/*_The advantage of multistage compression over single stage compression is? |
| A. | Lower power consumption per unit of air delivered |
| B. | Higher volumetric efficiency |
| C. | Decreased discharge temperature |
| D. | All of the above |
| Answer» E. | |
| 236. |
*/*_The maximum temperature in a gas turbine is? |
| A. | 200°C |
| B. | 500°C |
| C. | 700°C |
| D. | 1000°C |
| Answer» D. 1000¬¨‚àûC | |
| 237. |
%_In a jet engine, the air-fuel ratio is_% |
| A. | 30:1 |
| B. | 40:1 |
| C. | 50:1 |
| D. | 60:1 |
| Answer» E. | |
| 238. |
%_In a double acting compressor, the air is compressed_% |
| A. | In one cylinder |
| B. | In two cylinders |
| C. | In a single cylinder on both sides of the piston |
| D. | In two cylinders on both sides of the piston |
| Answer» D. In two cylinders on both sides of the piston | |
| 239. |
%_Isothermal compression though most efficient, but is not practicable because_% |
| A. | It requires very big cylinder |
| B. | It does not increase pressure much |
| C. | It is impossible in practice |
| D. | Compressor has to run at very slow speed to achieve it |
| Answer» E. | |
| 240. |
%_To avoid moisture troubles, the compressed air main line should_% |
| A. | Rise gradually towards the point of use |
| B. | Drop gradually towards the point of use |
| C. | Be laid vertically |
| D. | Be laid exactly horizontally |
| Answer» C. Be laid vertically | |
| 241. |
%_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚ÇÅ = Intake pressure of air, p‚ÇÇ = Inter-cooler pressure, and p‚ÇÉ = Delivery pressure of air)_% |
| A. | p‚ÇÇ = p‚ÇÅ √ó p‚ÇÉ |
| B. | p‚ÇÇ = p‚ÇÅ/p‚ÇÉ |
| C. | p‚ÇÇ = p‚ÇÅ √ó p‚ÇÇ |
| D. | p‚ÇÇ = p‚ÇÉ/p‚ÇÅ |
| Answer» D. p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö | |
| 242. |
%_Reheating in a multistage expansion gas turbine ________ compressor work._% |
| A. | Has no effect on |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» C. Increases | |
| 243. |
%_Ratio of indicated H.P. and brake H.P. is known as_% |
| A. | Mechanical efficiency |
| B. | Volumetric efficiency |
| C. | Isothermal efficiency |
| D. | Adiabatic efficiency |
| Answer» B. Volumetric efficiency | |
| 244. |
%_The volume of air sucked by the compressor during its suction stroke is called_% |
| A. | Free air delivery |
| B. | Compressor capacity |
| C. | Swept volume |
| D. | None of these |
| Answer» D. None of these | |
| 245. |
%_Gas turbine works on_% |
| A. | Brayton or Atkinson cycle |
| B. | Carnot cycle |
| C. | Rankine cycle |
| D. | Ericsson cycle |
| Answer» B. Carnot cycle | |
| 246. |
%_In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of_% |
| A. | Vacuum |
| B. | Atmospheric air |
| C. | Compressed air |
| D. | Oxygen alone |
| Answer» D. Oxygen alone | |
| 247. |
%_The net work input required for compressor with increase in clearance volume_% |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | Increases/decreases depending on compressor capacity |
| Answer» D. Increases/decreases depending on compressor capacity | |
| 248. |
_ Which of the following statement is correct as regard to centrifugal compressors?$? |
| A. | The flow of air is parallel to the axis of the compressor |
| B. | The static pressure of air in the impeller increases in order to provide centripetal force on the air |
| C. | The impeller rotates at high speeds |
| D. | The maximum efficiency is higher than multistage axial flow compressors |
| Answer» C. The impeller rotates at high speeds | |
| 249. |
_ If the flow of air through the compressor is parallel to its axis, then the compressor is$? |
| A. | Reciprocating compressor |
| B. | Centrifugal compressor |
| C. | Axial flow compressor |
| D. | Turbo compressor |
| Answer» D. Turbo compressor | |
| 250. |
_ Mechanical efficiency of gas turbines as compared to I.C engines is$? |
| A. | Higher |
| B. | Lower |
| C. | Same |
| D. | None of the above |
| Answer» B. Lower | |