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Mechanical Engineering :: Thermodynamics

  1. The efficiency of Diesel cycle increases with

  2. A.

     Increase in cut-off

    B.

     Constant cut-off

    C.

     Decrease in cut-off

    D.

     None of these


  3. The efficiency of Carnot cycle is maximum for

  4. A.

     Gas engine

    B.

     Petrol engine

    C.

     Steam engine

    D.

     Reversible engine


  5. Boyle's law i.e. pV = constant is applicable to gases under

  6. A.

     All ranges of pressures

    B.

     Only small range of pressures

    C.

     High range of pressures

    D.

     Steady change of pressures


  7. The state of a substance whose evaporation from its liquid state is complete, is known as

  8. A.

     Perfect gas

    B.

     Vapour

    C.

     Steam

    D.

     Air


  9. For a perfect gas, according to Boyle’s law (where P = Absolute pressure, V = Volume and T = Absolute temperature)

  10. A.

     V/T = constant, if p is kept constant

    B.

     P v = constant, if T is kept constant

    C.

     T/P = constant, if v is kept constant

    D.

     P/T = constant, if v is kept constant


  11. For a perfect gas, according to Boyle's law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)

  12. A.

     p v = constant, if T is kept constant

    B.

     v/T = constant, if p is kept constant

    C.

     p/T = constant, if v is kept constant

    D.

     T/p = constant, if v is kept constant


  13. A closed system is one in which

  14. A.

     Mass does not cross boundaries of the system, though energy may do so

    B.

     Mass crosses the boundary but not the energy

    C.

     Neither mass nor energy crosses the boundaries of the system

    D.

     Both energy and mass cross the boundaries of the system


  15. An isolated system is one in which

  16. A.

     Mass does not cross boundaries of the system, though energy may do so

    B.

     Neither mass nor energy crosses the boundaries of the system

    C.

     Both energy and mass cross the boundaries of the system

    D.

     Mass crosses the boundary but not the energy


  17. An open system is one in which

  18. A.

     Mass does not cross boundaries of the system, though energy may do so

    B.

     Neither mass nor energy crosses the boundaries of the system

    C.

     Both energy and mass cross the boundaries of the system

    D.

     Mass crosses the boundary but not the energy


  19. Which of the following gas has a minimum molecular mass?

  20. A.

     Nitrogen

    B.

     Hydrogen

    C.

     Methane

    D.

     Oxygen