10 The exergy of an isolated system never decreases T F 11 T

10. The exergy of an isolated system never decreases. T F 11. The working fluid remains in gaseous phase throughout a gas power cycle. T F 12. The thermal efficiency of an Otto cycle increases as the compression ratio increases. T F 13. Under the air standard assumptions, the exhaust process is replaced by a heat rejection.TF 14. The ideal Rankine cycle consists of two isentropic and two isobaric pracesses T F 15. Exergy, energy and entropy are properties of a system. 16. Cl engines need aspark plug to initiate the combustion process 17. Energy can be created, but cannot be destroyed T F 18. In gas power cycles, the working fluid changes its phase throughout the cycle. T F 19. Under the air standard assumptions, theexhaust ppcess isseplaced byabeatceiectian process T F 20. The Ideal Rankine cycle consists of two isentropic and two constant pressure processes. TF 21. In steam power plants, Hao enters the condenser as saturated liquid. 22. In steam power plants, H2o leaves the pump as compressed liquid. 23. The ideal Otto cycle consists of a constant volume heat addition process. 24. The SI and Cl engines differ from each other in the way the combustion is initiated. T F

Solution

10. The exergy of an isolted system never decreses -false

11.The working fluid remains in gaseous phase throughout a gas power cycle -true

12.the thermal effieciency of ottocycle increases as the compression ratio increases - True

13. under the air standard assumptions, the exhaust process is replaced by heat rejection -true

14.the ideal rankine cycle consists of two isentropic and two isobaric process - True

15. exergy, energy and entropy are properties of a system - True

16.CI engines need a spark plug to intitate the combustion procees - false

17. energy can be created, but cannot be destoryed

    a) energy neither be created nor be destroyed

18. in gas power cycles,the working fluid changes its phase throughout the cycles - false

19.under the air standard assumptions, the exhaust process is replaced by heat rejection -true

20.the ideal rankine cycle consists of two isentropic and two isobaric process - True

21.in steam power plants, h₂o enters the condesers as saturated liquid - false

22. in steam power plant the leaves the pump compressed liquid - true

23. the ideal otto cycle consists of a constant volume heat additions process - true

24. the si and ci engine differ from each other in the way the combustion process - true

1. the si and ci engine are both intrenal combustion engines - true

2. the efficiency of an ideal otto cycle is higher than the carnot efficiency between the same temperature limits- false

3. in steam power plants, H₂O enters the pump as compressed - false

4.under the air standard assumptions, the exhaust process is replaced by heat rejection -true

5. iin vapour power cycle the working fluid remians in gaseous phase throughout the cycle - false

6. ideal rankine cycle consists of two isentropic and two isothermall process -false

7. in steam power palnts, H2O enters the boiler as compressed liquid - true

8. ins steam power plant, h2O leaves the turbine as superheated - false

9. exergy and energy are both properties of a system - false

25. in steam power palnt h2o enters the turbine at saturated liquid - false

26.in steam power plant h2o leaves the boiler as compressed liquid - false

27.the exergy destroyed in an isentropic process is zero - false

28. the thermal effiecency of an otto cycle decreses as the compression ratio decreases -true

29. the ideal rakine cycle consists of two isentropic and two isobaric process - true

30. the working fluid remians in vapour state throughout vapour cycle - false

31. in steam power plants h2o leaves the condeser as compressor liquid - false

32. in steam power plants, h2o leaves the turbine as a high quality mixture- false

33. in steam power plants, h2o leaves the pumps as saturated liquid - false

34. the thermal effieciency of an otto cycle with a compression ratio of 10 is 60.18%

35.in rankine cycle h2o enters the bioler as compressed liquid

36. diesel cycle and otto cycle are the ideal cycles of diesel engine and petrol engines respectively