The maximum propulsion efficiency of a turbojet is attained at around following speed __________________?

Related Mcqs:

1. Propulsion efficiency of the following order-is obtained in practice _______________?

   A. 34%
   B. 50%
   C. 60%
   D. 72%
   E. 85%.

2. Turbo propeller has the following additional feature over the turbojet __________________?

   A. peopeller
   B. diffuser
   C. intercooler
   D. turbine and combustion chamber
   E. starting engine

3. Which of the following fuels can be used in turbojet engines _____________________?

   A. liquid hydrogne
   B. high speed diesel oil
   C. kerosene
   D. demethylated spirit
   E. methyl alcohol

4. The power available for take off and climb in case of turbojet engine as compared to reciprocating engine is ___________________?

   A. less
   B. more
   C. same
   D. may be less or more depending on ambient conditons
   E. unpredictable

5. Ram compression in turbojet involves____________________?

   A. reduction of speed of incoming air and conversion of part of it into pressure energy
   B. compression of inlet air
   C. increasing speed of incoming air
   D. lost work
   E. leakage losses

6. There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would__________________?

   A. remain same
   B. decrease
   C. increase
   D. unpredictable
   E. none of the above

7. In jet propulsion power unit, the inlet duct of diverging shape is used in order to _______________ ?

   A. collect more air
   B. convert kinetic energy of air into pres-sure energy
   C. provide robust structure
   D. beautify the shape
   E. none of the above

8. 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
   E. isothermally

9. Isothermal compression efficiency, even when running at high speed, can be approached by using A. multi-stage compression B. cold water spray C. both A. and B. above D. fully insulating the cylinder E. high stroke_________________?

   Isothermal compression efficiency, even when running at high speed, can be approached by using
   A. multi-stage compression
   B. cold water spray
   C. both A. and B. above
   D. fully insulating the cylinder
   E. high stroke

10. The volumetirc efficiency of a compressor is calculated on the basis of __________________?

    A. volume of air inhaled at working conditions
    B. volume of air inhaled at N.T.P. conditions
    C. volume at 0°C and 1 kg/cm2
    D. volume at 20°C and 1 kg/cm2
    E. none of the above