MCQOPTIONS
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MCQOPTIONS
This section includes 4791 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 4251. |
The brake power is always greater than indicated power. |
| A. | Agree |
| B. | Disagree |
| Answer» C. | |
| 4252. |
Iso-octane (C8H18) has octane number of |
| A. | 0 |
| B. | 50 |
| C. | 100 |
| D. | 120 |
| Answer» D. 120 | |
| 4253. |
An ignition coil in the spark ignition engines supplies __________ voltage to the spark plug. |
| A. | high |
| B. | low |
| Answer» B. low | |
| 4254. |
The operation of forcing additional air under pressure into the engine cylinder is known as |
| A. | supercharging |
| B. | carburation |
| C. | turbulence |
| D. | delay period |
| Answer» B. carburation | |
| 4255. |
If the speed of the engine is increased, the indicated power will |
| A. | increase |
| B. | decrease |
| C. | remain same |
| Answer» B. decrease | |
| 4256. |
The petrol engines are also known as __________ engines. |
| A. | compression ignition |
| B. | spark ignition |
| Answer» C. | |
| 4257. |
The specific fuel consumption per B.P. hour for a petrol engine is about |
| A. | 0.2 kg |
| B. | 0.25 kg |
| C. | 0.3 kg |
| D. | 0.35 kg |
| Answer» C. 0.3 kg | |
| 4258. |
The material most commonly used for sheilding is |
| A. | carbon |
| B. | lead |
| C. | concrete |
| D. | all of these |
| Answer» D. all of these | |
| 4259. |
Light weight substances can not be effective moderators. |
| A. | True |
| B. | False |
| Answer» C. | |
| 4260. |
Theoretically, a four stroke cycle engine should develop __________ power as that of a two stroke cycle engine. |
| A. | half |
| B. | same |
| C. | double |
| D. | four times |
| Answer» B. same | |
| 4261. |
A nuclear reactor is said to be critical when the neutron population in the reactor core is |
| A. | rapidly increasing leading to the point of explosion |
| B. | decreasing from the specified value |
| C. | reduced to zero |
| D. | constant |
| Answer» E. | |
| 4262. |
The efficiency of the vane blower is (where W1 = Workdone due to compression, and W2 = Workdone due to back flow) |
| A. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/375-103-1.png"> |
| B. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/375-103-2.png"> |
| C. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/375-103-3.png"> |
| D. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/375-103-4.png"> |
| Answer» C. <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/375-103-3.png"> | |
| 4263. |
The volumetric efficiency of a compressor |
| A. | constant with decrease in compression ratio |
| B. | decreases with decrease in compression ratio |
| C. | increases with increase in compression ratio |
| D. | decreases with increase in compression ratio |
| Answer» E. | |
| 4264. |
The performance of air compressor at high altitudes will be __________ as compared to that at sea level. |
| A. | same |
| B. | lower |
| C. | higher |
| Answer» C. higher | |
| 4265. |
In a centrifugal compressor, the highest Mach number leading to shock wave in the fluid flow occurs at |
| A. | diffuser inlet radius |
| B. | diffuser outlet radius |
| C. | impeller inlet radius |
| D. | impeller outlet radius |
| Answer» C. impeller inlet radius | |
| 4266. |
Standard air is the air at __________ and relative humidity of 36 percent. |
| A. | 0.1 bar and 20 C |
| B. | 1 bar and 20 C |
| C. | 0.1 bar and 40 C |
| D. | 1 bar and 40 C |
| Answer» C. 0.1 bar and 40 C | |
| 4267. |
The compressor capacity is defined as the |
| A. | actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions |
| B. | volume of air delivered by the compressor |
| C. | volume of air sucked by the compressor during its suction stroke |
| D. | none of the above |
| Answer» C. volume of air sucked by the compressor during its suction stroke | |
| 4268. |
In n1 and n2 are the indices of compression for the first and second stage of compression, then the ratio of workdone on the first and second stages (W1/W2) with perfect intercoooing is given by |
| A. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/372-68-1.png"> |
| B. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/372-68-2.png"> |
| C. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/372-68-3.png"> |
| D. | <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/372-68-4.png"> |
| Answer» C. <img src="/_files/images/mechanical-engineering/compressors-gas-dynamics-and-gas-turbines/372-68-3.png"> | |
| 4269. |
The speed of rotary air compressor is __________ as compared to reciprocating air compressor. |
| A. | high |
| B. | low |
| Answer» B. low | |
| 4270. |
The operation of the reciprocating air motor is similar to reciprocating air compressor. |
| A. | True |
| B. | False |
| Answer» C. | |
| 4271. |
When air is to be compressed at a high pressure, then it is advantageous to use |
| A. | single stage compression |
| B. | multi-stage compression without intercooling |
| C. | multi-stage compression with intercooling |
| D. | none of these |
| Answer» D. none of these | |
| 4272. |
The absolute pressure of air at the outlet of a compressor is called |
| A. | back pressure |
| B. | critical pressure |
| C. | discharge pressure |
| D. | none of these |
| Answer» D. none of these | |
| 4273. |
The volumetric efficiency of the compressor is defined as the ratio of volume of free air delivery per stroke to the swept volume of the piston. |
| A. | Yes |
| B. | No |
| Answer» B. No | |
| 4274. |
A compressor must be driven by some prime mover. |
| A. | Agree |
| B. | Disagree |
| Answer» B. Disagree | |
| 4275. |
Volumetric efficiency of a compressor decreases with __________ in compression ratio. |
| A. | decrease |
| B. | increase |
| Answer» C. | |
| 4276. |
In a closed cycle gas turbine, the air is compressed |
| A. | isothermally |
| B. | polytropically |
| C. | isentropically |
| D. | none of these |
| Answer» D. none of these | |
| 4277. |
A simple turbo-jet engine is basically a gas turbine engine equipped with a propulsive nozzle and diffuser. |
| A. | Agree |
| B. | Disagree |
| Answer» B. Disagree | |
| 4278. |
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 | |
| 4279. |
The gas in cooling chamber of a closed cycle gas turbine is cooled at |
| A. | constant volume |
| B. | constant temperature |
| C. | constant pressure |
| D. | none of these |
| Answer» D. none of these | |
| 4280. |
The compression ratio for the compressor is always __________ unity. |
| A. | equal to |
| B. | less than |
| C. | more than |
| Answer» D. | |
| 4281. |
The assumption made in two stage compression with intercooler is that |
| A. | there is no pressure drop in the intercooler |
| B. | the compression in both the cylinders is polytropic |
| C. | the suction and delivery of air takes place at constant pressure |
| D. | all of the above |
| Answer» E. | |
| 4282. |
With the decrease in compression ratio, the volumetric efficiency |
| A. | does not change |
| B. | increases |
| C. | decreases |
| Answer» C. decreases | |
| 4283. |
Separators are generally used in air compressor installations |
| A. | before the intercooler |
| B. | after the intercooler |
| C. | between the aftercooler and receiver |
| D. | before first stage suction |
| Answer» D. before first stage suction | |
| 4284. |
For minimum work required to compress and deliver a quantity of air by multi-stage compression, |
| A. | the compression ratio in each stage should be same |
| B. | the intercooling should be perfect |
| C. | the workdone in each stage should be same |
| D. | all of the above |
| Answer» E. | |
| 4285. |
If the flow of air through the compressor is perpendicular to its axis, then it is a |
| A. | reciprocating compressor |
| B. | centrifugal compressor |
| C. | axial flow compressor |
| D. | turbo compressor |
| Answer» C. axial flow compressor | |
| 4286. |
In air compressors, free air delivery means the |
| A. | actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions |
| B. | volume of air delivered by the compressor |
| C. | volume of air sucked by the compressor during its suction stroke |
| D. | none of the above |
| Answer» B. volume of air delivered by the compressor | |
| 4287. |
The workdone on a compressor will be minimum if air is taken from |
| A. | the atmosphere |
| B. | a source at 0 C |
| C. | a source of low temperature air |
| D. | a source of high temperature air |
| Answer» D. a source of high temperature air | |
| 4288. |
In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into |
| A. | atmosphere |
| B. | vacuum |
| C. | discharge nozzle |
| D. | back to the compressor |
| Answer» D. back to the compressor | |
| 4289. |
The overall isothermal efficiency of the compressor is defined as the ratio of |
| A. | work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio |
| B. | isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor |
| C. | volume of free air delivery per stroke to the swept volume of the piston |
| D. | isentropic power to the power required to drive the compressor |
| Answer» C. volume of free air delivery per stroke to the swept volume of the piston | |
| 4290. |
The minimum work required for a three stage reciprocating air compressor is __________ the work required for each stage. |
| A. | equal to |
| B. | double |
| C. | three times |
| D. | six times |
| Answer» D. six times | |
| 4291. |
The air power of the compressor is also known as |
| A. | indicated power |
| B. | brake power |
| C. | frictional power |
| D. | none of these |
| Answer» B. brake power | |
| 4292. |
For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4293. |
Slip factor in a centrifugal compressor indicates the amount of air leaked from the storage vessel. |
| A. | Yes |
| B. | No |
| Answer» C. | |
| 4294. |
A turbo-prop is preferred to turbo-jet because |
| A. | it has high propulsive efficiency at high speeds |
| B. | it can fly at super sonic speeds |
| C. | it can fly at high elevations |
| D. | it has high power for take off |
| Answer» E. | |
| 4295. |
In a two stage reciprocating compressor with intercooler, the amount of work saved with incomplete intercooling is __________ that in case of complete intercooling. |
| A. | less than |
| B. | more than |
| Answer» B. more than | |
| 4296. |
In a centrifugal compressor, the flow of air is __________ to the axis of compressor. |
| A. | parallel |
| B. | perpendicular |
| C. | inclined |
| D. | none of these |
| Answer» C. inclined | |
| 4297. |
In axial flow compressors, the flow of air is parallel to the axis of compressor. |
| A. | Correct |
| B. | Incorrect |
| Answer» B. Incorrect | |
| 4298. |
The ratio of the isothermal power to the shaft power or brake power of the motor or engine required to drive the compressor is called overall isothermal efficiency. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4299. |
In a high pressure compressor, the delivery pressure is |
| A. | 1 to 5 bar |
| B. | 5 to 8 bar |
| C. | 8 to 10 bar |
| D. | 10 to 15 bar |
| Answer» D. 10 to 15 bar | |
| 4300. |
When the outlet angle from the rotor of a centrifugal compressor is more than 90 , then the blades are said to be |
| A. | forward curved |
| B. | backward curved |
| C. | radial |
| D. | none of these |
| Answer» B. backward curved | |