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Compressors, Gas Turbines And Jet Engines MCQ
300 Important Compressors, Gas Turbines And Jet Engines MCQ Question and Answer | PDF Free Download
1.The pressure and temperature conditions of air at the suction of compressor are
- AAtmospheric
- BSlightly more than atmospheric
- CSlightly less than atmospheric
- DPressure slightly less than atmospheric and temperature slightly more than atmospheric
2.If p₁, is the pressure of air entering the L.P. cylinder and p₂ is the pressure of air leaving the L.P. cylinder (or inter-cooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D₁ = Dia. of L.P. cylinder, and D₂ = Dia. of H.P. cylinder)
- AD₁/D₂ = p₁ p₂
- BD₁/D₂ = p₁/p₂
- CD₁/D₂ = p₂/p₁
- DNone of these
3.During peak load periods, the best method of controlling compressors is
- AStart-stop motor
- BConstant speed unloader
- CRelief valve
- DVariable speed
4.The efficiency of roots blower ________ with the increase in pressure ratio.
- ADecreases
- BIncreases
- CDoes not change
- DNone of these
5.The work done per unit mass of air in compression will be least when 'n' is equal to
- A1
- B1.2
- C1.3
- D1.4
6.Ratio of compression is the ratio of
- AGauge discharge pressure to the gauge intake pressure
- BAbsolute discharge pressure to the absolute intake pressure
- CPressures at discharge and suction corresponding to same temperature
- DStroke volume and clearance volume
7.Adiabatic compression is one in which
- ATemperature during compression remains constant
- BNo heat leaves or enters the compressor cylinder during compression
- CTemperature rise follows a linear relationship
- DWork done is maximum
8.The thrust on the rotor in a centrifugal compressor is produced by
- ARadial component
- BAxial component
- CTangential component
- DNone of the above
9.For supplying intermittent small quantity of air at high pressure, following compressor is best suited
- ACentrifugal
- BReciprocating
- CAxial
- DScrew
10.Out of the following, from where you will prefer to take intake for air compressor
- AFrom an air conditioned room maintained at 20°C
- BFrom outside atmosphere at 1°C
- CFrom coal yard side
- DFrom a side where cooling tower is located nearby
11.In a single stage, single acting reciprocating air compressor, without clearance, the work-done on the air during isentropic compression is ________ the heat required to raise the temperature of air from T₁ to T₂ at a constant pressure.
- AEqual to
- BLess than
- CGreater than
- DNone of these
12.In multistage compressor, the isothermal compression is achieved by
- AEmploying inter-cooler
- BBy constantly cooling the cylinder
- CBy running compressor at very slow speed
- DBy insulating the cylinder
13.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
- AIncrease
- BDecrease
- CRemain unaffected
- DOther factors control it
14.The process, which causes the air to enter the impeller blades of a centrifugal compressor at ________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.
- AReduced
- BIncreased
- CZero
- DNone of these
15.Fighter bombers use following type of engine
- ATurbojet
- BTurbo-propeller
- CRocket
- DRamjet
16.Fighter bombers use following type of engine
- ATurbojet
- BTurbo-propeller
- CRocket
- DRamjet
17.Isothermal compression efficiency can be attained by running the compressor
- AAt very high speed
- BAt very slow speed
- CAt average speed
- DAt zero speed
18.Inter cooling in compressors
- ACools the delivered air
- BResults in saving of power in compressing a given volume to given pressure
- CIs the standard practice for big compressors
- DEnables compression in two stages
19.The volume of air delivered by the compressor is called
- AFree air delivery
- BCompressor capacity
- CSwept volume
- DNone of these
20.The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called
- ASlip factor
- BVelocity factor
- CVelocity coefficient
- DNone of the above