QA- STEAM POWER CYCLE Objective Q&A

1. The path followed in a vapour power cycle is

A) Boiler-Condenser-Turbine-Pump               B) Boiler-Turbine-Condenser-Pump

C) Boiler-Turbine-Pump-Condenser              D) Boiler-Pump-Turbine-Condenser

 

2. For a vapour power cycle,

A) Net Heat Input Is Converted Into Net Work Output                

B) Q₁-Q₂ = W_t -W_p

C) Efficiency = 1 – (Q₂/Q₁)                                                               

D) All of the Mentioned

 

3. For a Rankine cycle, which of the following is true?

A)  A Reversible Constant Pressure Heating Process Happens In Steam Boiler

B)  Reversible Adiabatic Expansion Of Steam In Turbine

C)  Reversible Constant Pressure Heat Rejection In Condenser

D) All of the Mentioned

 

4. The work ratio is defined as the ratio of

A) Positive Work Output to Net Work Output                             

B) Net Work Output to Positive Work Output

C)  Heat Input to Work Output                                         

D)  None of the Mentioned

 

5.  Heat rate is given by (in kJ/kWh)

A) Cycle Efficiency                                            B) 3600 / Cycle Efficiency                

C) Cycle Efficiency / 3600                                   D) Cycle Efficiency x 3600

 

6. Which of the following statement is true?

A)  During Compression, Specific Volume of the Fluid Should Be Kept Small

B)  During Expansion, Specific Volume of the Fluid Should Be Kept Large

C) Both of the Mentioned                                                                  

D) None of the Mentioned

 

7. The liquid water handled by pump is

A)  Incompressible                      

B)  With Increase in Pressure, There Is A Little Change in Density or Specific Volume

C) Both of the Mentioned   

D) None of the Mentioned

8. For a fluid undergoing cycle process, 

A)  There Is No Net Change in Its Internal Energy     

B)  Energy Transfer As Heat Is Equal to the Energy Transfer as Work

C) Both of the Mentioned                                              

D) None of the Mentioned

 

9. Work output of turbine is ____ the work input to the pump.

A) Much Larger                                    B) Much Smaller

C) Equal to

                                          D) None of the Mentioned

 

10. The thermal efficiency of the cycle is

A) Q₂ / W_net                    B) W_net / Q₂               C) W_net / Q₁               D) Q₁ / W_net

 

11. Which of the following losses occur in a cycle?

A) Piping Losses		B) Pump Losses
C) Turbine Losses                                  12. The important piping losses include		D) All of the Mentioned
A) Pressure Drop Due To Friction		B) Heat Loss To Surroundings
C) Both of the Mentioned                     13. The losses in boiler include		D) None of the Mentioned
A) Pressure Drop from Pump to Boiler		B) Pressure Drop in Boiler
C) Both of the Mentioned                   14. The main losses in turbine include		D) None of the Mentioned
A) Heat Loss to Surroundings		B) Friction Losses
C) Both of the Mentioned                     15.  The losses in condenser are ____		D) None of the Mentioned
A) Small		B) Large
C) Always Constant                               16. The condenser losses include		D) None of the Mentioned
A) Loss of Pressure		B) Cooling of Condensate Below Saturation Temperature
C) Both of the Mentioned		D) None of the Mentioned

17. The efficiency of Carnot cycle is ____ the efficiency of Rankine cycle.

A) Less than          B) Greater than         C) Equal to        D) None of the Mentioned 

 

18. The only process which is different in Carnot and Rankine cycle is

A) Compression in Pump                                 B) Expansion In Turbine       

C) Heat Rejection Process                               D) Heat Addition Process

 

19. In the Rankine cycle, heat is added reversibly at

A) Constant Pressure and Constant Temperature  

B) Constant Pressure and Infinite Temperature

C) Infinite Pressure and Constant Temperature  

D) Infinite Pressure and Infinite Temperature

 

20. The efficiency of Rankine cycle is given by

A) 1 – (Q₁/Q₂) 

B) 1 – (T_mean/T₂)    

C) 1 – (T₂/T_mean) 

D) None of the Mentioned

 

21. Which of the following statement is true?

A)  For Given T_mean, Lower Is The T₂, Higher Will Be The Efficiency of Rankine Cycle

B)  The Lowest Possible Temperature of Heat Rejection Is The Surroundings Temperature

C)  Higher Is The Mean Temperature of Heat Addition, Higher Will Be The Efficiency 

D) All of the Mentioned

 

22.  If we ____ the superheat at constant pressure then the cycle efficiency ____

A) Decrease, Increases                    B) Increase, Decreases       

C) Increase, Increases                    D) Decrease, Decreases

 

23. To prevent erosion of blades, quality should not fall below

A) 85%                B) 90%               C) 95%                 D) 100%

 

24. To fix the maximum steam pressure at the inlet of turbine we need to first fix

A)  The Maximum Steam Temperature at Turbine Inlet                          

B)  Minimum Temperature of Heat Rejection

C)  The Minimum Quality of Steam at Turbine Exhaust          

D) All of the Mentioned

25. Which of the following is true about a reheat cycle?

A)  Used To Limit The Quality At Turbine Exhaust At 0.85 When Steam Pressure Is Higher Than (P₁)Max

B)  After Partial Expansion In Turbine, Steam Is Brought Back To Boiler

C)  The Steam Is Reheated By Combustion Gases

D) All of the Mentioned

 

26. The correct sequence of expansion in a reheat cycle is

A) HP Turbine – LP Turbine – Constant Pressure In Boiler 

B) HP Turbine – Constant Pressure In Boiler – LP Turbine

C)  LP Turbine – Constant Pressure In Boiler – HP Turbine

D)  LP Turbine – HP Turbine – Constant Pressure In Boiler

 

27. Why is steam not allowed to expand deep into two-phase region before being taken for reheating?

A)  To Protect the Reheater Tubes                  

B)  To Prevent Solid Deposits Being Left Behind While Evaporating

C) Both of the Mentioned                                                  

D) None of the Mentioned

 

28. Why should the reheat pressure be optimized?

A)  A Low Reheat Pressure Brings Down the Mean Temperature of Heat Addition and Hence the Cycle Efficiency

B)  A High Reheat Pressure Increases the Moisture Content at Turbine Exhaust

C) Both of the Mentioned                                                  

D) None of the Mentioned

 

29. The optimum reheat pressure is ____ times that of the initial steam pressure.

A)  0.2                                                                                      

B)  0.23   

C)  0.25                                                                   

D) All of the Mentioned

 

30. With the use of reheat, 

A)  The Net Work Output of The Plant Increases    

B)  There Is Only a Marginal Increase in Cycle Efficiency

C)  The Quality of Steam at Turbine Exhaust Is Kept Within a Limit                 

D) All of the Mentioned

31. The mean temperature of heat addition can be increased by

A)  Increasing the Amount of Heat Supplied at High Temperatures 

B)  Decreasing the Amount of Heat Added At Low Temperatures

C) Both of the Mentioned                                                  

D) None of the Mentioned

 

32. The efficiency of an ideal regenerative cycle is given by

A) 1 – (T₁/T₂)                    B) 1 – (T₂/T₁)                        

C) 1 – (Q₁/Q₂)                  D) None of the Mentioned

 

33. The efficiency of an ideal regenerative cycle is ____ the Carnot cycle efficiency.

A) Greater than                            B) Equal to                           

C) Less than                                 D) None of the Mentioned

 

34. When compared with the Rankine cycle, the ideal regenerative cycle has

A) Less Net Work Output                        B) More Steam Rate                           

C) More Efficient                                     D) All of the Mentioned

 

35. The ideal regenerative cycle is not practicable because

A)  Reversible Heat Transfer Can’t Be Obtained In Finite Time

B)  Heat Exchanger In Turbine Is Mechanically Impracticable

C)  There Is High Moisture Content of Steam In The Turbine

D)  All of the Mentioned

 

36. The efficiency of regenerative cycle will be ____ the efficiency of the Rankine cycle.

A) Greater than                B) Equal to                           

C) Less than                     D) None of the Mentioned

 

37. Which of the following is an assumption for heaters?

A) They Are Adequately Insulated       

                          

B) There Is No Heat Gain From or Heat Loss to the Surroundings 

C) Both of the Mentioned                                                

D) None of the Mentioned

 

38. The reheating of steam is used when the vaporization pressure is ____.

A) Low             B) High            C) Both When Low or High              D) Always

39. Why both reheating and regeneration is used together?

A)  The Effect of Reheat Alone On Efficiency Is Very Small 

B)  Regeneration Has a Marked Effect on Efficiency

C) Both of the Mentioned                                                                  

D) None of the Mentioned

 

40. How many types of feed water heaters are present?

A) One               B) Two                   C) Three                 D) Four

 

41. The temperature of feed water leaving a heater is ____ the saturation temperature at steam extraction pressure.

A) Less than                              B) Equal to                           

C) More than                             D) None of the Mentioned

 

42. Which of the following statement is true?

A)  Open Heater Is Also Known As Contact-Type Heater

B)  In An Open Type Heater The Extracted Or Bled Steam Is Allowed To Mix With The Feed water

C)  In A Closed Heater, The Fluids Are Not Allowed To Mix Together 

D) All of the Mentioned

 

43. Which of the following is true for an open heater?

A) It Is Simple, Has Low Cost and Low Heat Transfer Capacity           

B) A Pump Is Required At Each Heater

C)  Both of the Mentioned                                                                                  

D)  None of the Mentioned

 

44. Which of the following is true for a closed heater?

A)  It Requires a Single Pump Regardless of the Number of Heaters 

B)  It Is Costly

C) Both of the Mentioned                                                                                  

D) None of the Mentioned

 

45. The higher the number of heaters used, the ____ will be the cycle efficiency.

A) Lower                                     

B) Higher          

C) Efficiency Does Not Depend On Number of Heaters                            

D) None of the Mentioned

46. The thermal irreversibility should be ____ to improve the performance.

A) Reduced                                     B) Increased                         

C) Kept Constant                           D) None of the Mentioned

 

47. The working fluid should have ____ critical temperature.

A) Low                                           B) High                  

C) It Does Not Matter                    D) None of the Mentioned

 

48. The saturation pressure at heat rejection temperature should be ____ atmospheric pressure.

A) Equal To                                   B) Below                                

C) Above                                      D) None of the Mentioned

 

49. Why is superheat desired?

A) To Reduce Piping Losses                   B) To Improve Efficiency        

C) Both of the Mentioned                      D) None of the Mentioned

 

50. Which of the following fluid can be used in place of water?

A) Diphenyl Ether                            B) Aluminum Bromide                      

C) Mercury                                      D) All of the Mentioned

 

51. Which of the following statement is true?

A)  Only Mercury Has Been Used In Place Of Water                

B)  Diphenyl Ether Decomposes At High Temperatures

C) Both of the Mentioned                                                  

D) None of the Mentioned

 

52. Why is mercury unsuitable at low temperatures?

A)  Its Saturation Pressure Becomes Very High          

B)  Its Specific Volume Is Very Low At Such a High Pressure

C)  Both of the Mentioned                                                                  

D)  None of the Mentioned

 

53. In a binary cycle, ____ cycles with ____ working fluid are coupled.

A) Two, Same                               B) Two, Different                                

C) Three, Same                            D) Three, Different

54. When mercury cycle is added to the steam cycle,

A) The Mean Temperature Of Heat Addition Increases           

B)  Efficiency Decreases

C)  Maximum Pressure Is High                                                        

D)  All of the Mentioned

 

55. In a mercury-steam cycle, mercury cycle is called ____ and steam cycle is called ____

A) Bottoming Cycle, Topping Cycle                              

B) Topping Cycle, Bottoming Cycle

C) Both Are Called Bottoming Cycle                             

D) Both Are Called Topping Cycle

 

56. Rankine cycle efficiency of a good Steam Power Plant may be in the range of?

A) 15 To 20%                                                                     

B) 35 To 45%                       

C) 70 To 80%                                                                      

D) 90 To 95%

 

57. Which of these is sometimes neglected?

A) Turbine Work                                                                 

B) Pump Work                    

C) Condenser Heat                                                             

D) Boiler Heat

 

58.  Efficiency of a Rankine Cycle is also expressed as__________

A) Capacity Ratio                                                              

B) Heat Rate                         

C) Heat Ratio                                                                     

D) Steam Rate

 

59. Steam Power Plants are more popular in electric power generation because

A) Work Output Of Turbine Is Very Large Than Work Input To The Pump

B)  Work Output Of Turbine Is Very Small Than Work Input To The Pump

C)  Work Output Of Turbine Is Equal To Work Input To The Pump

D)  None of the Mentioned.

 

60. In Rankine Cycle, water is converted to saturated liquid in ___________

A) Evaporator                                                                    

B) Economizer                     

C) Superheater                                                                   

D) Preheater

 

Composed By:

R.Satheesh, M.E., Asso.Prof.,

 

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