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MCQOPTIONS
This section includes 327 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.
| 301. |
The compressor performance at higher altitude compared to sea level will be |
| A. | same |
| B. | higher |
| C. | lower |
| D. | dependent on other factors |
| Answer» D. dependent on other factors | |
| 302. |
The compressor efficiecny is the |
| A. | isothermal H.P/indicated H.R |
| B. | isothermal H.P./shaft H.R |
| C. | total output/air input |
| D. | compression work/motor input |
| Answer» B. isothermal H.P./shaft H.R | |
| 303. |
An air compressor may be controlled by |
| A. | throttle control (b) clearance control |
| B. | blow-off control |
| C. | any one of the above |
| D. | none of the above. |
| Answer» E. | |
| 304. |
The area of actual indicator diagram on an air compressor as compared to area of ideal indicator diagram is |
| A. | less |
| B. | more |
| C. | same |
| D. | more/less depending on compressor capacity |
| Answer» C. same | |
| 305. |
After-cooler is used to |
| A. | cool the air |
| B. | decrease the delivery temperature for ease in handling |
| C. | cause moisture and oil vapour to drop out |
| D. | reduce volume |
| Answer» D. reduce volume | |
| 306. |
The capacity of compressor will be highest when its intake temperature is |
| A. | lowest |
| B. | highest |
| C. | anything. |
| D. | atmospheric |
| Answer» E. | |
| 307. |
Rotary compressor is best suited for |
| A. | large quantity of air at high pressure |
| B. | small quantity of air at high pressure |
| C. | small quantity of air at low pressure |
| D. | large quantity of air at low pressure |
| Answer» C. small quantity of air at low pressure | |
| 308. |
Reciprocating air compressor is best suited for |
| A. | large quantity of air at high pressure |
| B. | small quantity of air at high pressure |
| C. | small quantity of air at low pressure |
| D. | large quantity of air at low pressure |
| Answer» B. small quantity of air at high pressure | |
| 309. |
Which is false statement about air receivers |
| A. | These are used to dampen pulsations |
| B. | These act as reservoir to- take care of sudden demands |
| C. | These increase compressor efficiency |
| D. | These knock out some oil and moisture |
| Answer» D. These knock out some oil and moisture | |
| 310. |
Mining industry usually employs following motive power |
| A. | A.C. electric motor |
| B. | compressed air |
| C. | petrol engine |
| D. | diesel engine |
| Answer» C. petrol engine | |
| 311. |
The clearance volume of the air compressor is kept minimum because |
| A. | it allows maximum compression to be achieved |
| B. | it greatly affects volumetric efficiency |
| C. | it results in minimum work |
| D. | it permits isothermal compression |
| Answer» C. it results in minimum work | |
| 312. |
Volumetric efficiency of a compressor without clearance volume |
| A. | increases with increase in compression ratio |
| B. | decreases with increase in compression ratio |
| C. | is not dependent upon compressin ratio |
| D. | unpredictable. |
| Answer» D. unpredictable. | |
| 313. |
Volumetric efficiency of a compressor with clearance volume |
| A. | increases with increase in compression ratio |
| B. | decreases with increase in compression ratio |
| C. | in not dependent upon compression ratio |
| D. | may increase/decrease depending on compressor capacity |
| Answer» C. in not dependent upon compression ratio | |
| 314. |
Ratio of indicated h.p. to shaft h.p. in known as |
| A. | compressor efficiency |
| B. | isothermal efficiency |
| C. | volumetric efficiency |
| D. | mechanical efficiency |
| Answer» E. | |
| 315. |
The net work input required for compressor with increase in clearance volume |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | increases/decreases depending on com-pressor capacity |
| Answer» D. increases/decreases depending on com-pressor capacity | |
| 316. |
Clearance volume in actual reciprocating compressors is essential |
| A. | to accommedate 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. | |
| 317. |
The ratio of work doen per cycle to the swept volume in case of compressor is called |
| A. | compression index |
| B. | compression ratio |
| C. | compressor efficiency |
| D. | mean effective pressure |
| Answer» E. | |
| 318. |
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 | |
| 319. |
Isothermal compression though most efficient, but is not -practicable because |
| A. | ityrequires 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. | |
| 320. |
The work done per unit mass of air in compression will'be least when n is equal to |
| A. | 1 |
| B. | 1.2 |
| C. | 1.3 |
| D. | 1.4 |
| Answer» B. 1.2 | |
| 321. |
An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes |
| A. | one adiabatic, two isobaric, and one constant volume |
| B. | two adiabatic and two isobaric |
| C. | two adiabatic, one isobaric and one constant volume |
| D. | one adiabatic, one isobaric and two constant volume |
| Answer» B. two adiabatic and two isobaric | |
| 322. |
Inter cooling in compressors |
| A. | cools the delivered air |
| B. | results in saving of power in compressing a given volume to given pressure |
| C. | is the standard practice for big compressors |
| D. | enables compression in two stages |
| Answer» C. is the standard practice for big compressors | |
| 323. |
Aeroplanes employ following type of compressor |
| A. | radial flow |
| B. | axial flow |
| C. | centrifugal |
| D. | combination of above |
| Answer» C. centrifugal | |
| 324. |
The compressor capacity with decrease in suction temperature |
| A. | increases |
| B. | decreases |
| C. | remains unaffected |
| D. | may increase or decrease depending on compressor capacity |
| Answer» B. decreases | |
| 325. |
Isothermal compression effeicency can be attained by running the compressor |
| A. | at very high speed |
| B. | at very slow speed |
| C. | at average speed |
| D. | at zero speed |
| Answer» C. at average speed | |
| 326. |
The pressure and temperature conditions of air at the suction of compressor are |
| A. | atmospheric |
| B. | slightly more than atmospheric |
| C. | slightly less than atmospheric |
| D. | pressure sightly less than atmospheric and temperature slightly more than atmospheric. |
| Answer» E. | |
| 327. |
The overall isothermal eiffciency of compressor is defined as the ratio of |
| A. | isothermal h.p. to the BHP of motor |
| B. | isothermal h.p. to adiabatic h.p. |
| C. | power to drive compressor to isothermal h.p. |
| D. | work to compress air isothermally to work for actual compression |
| Answer» B. isothermal h.p. to adiabatic h.p. | |