AIR STANDARD CYCLES

MULTIPLE CHOICE QUESTIONS

(MCQ) WITH ANSWERS 

MCQ increases knowledge, understanding

and clarity. One gains lot of confidence.

Carnot, Otto, Brayton and Diesel cycles are

air cycles. These are power producing

cycles. Basic principles are easily applied in

the real life applications.

1. A Carnot Cycle consists of

   • (a) Two isobaric and two isentropic processes

   • (b) Two isothermal and two isobaric processes

   • (c) Two isothermal and two isentropic processes

   • (d) None

ANS: ©

2. Otto cycle is also known as

   • (a) Constant pressure cycle

   • (b) Constant volume cycle

   • (c) Constant temperature cycle

   • (d) None

ANS: (b)

3. A cycle consisting of two iso-thermal and two constant volume processes is a

   • (a) Joule cycle

   • (b) Sterling Cycle

   • (c) Otto cycle

   • (d) None

ANS: (b)

4. For the same compression ratio the efficiency of diesel cycle is

   • (a) Greater than that of Otto cycle

   • (b) Equal to that of Otto Cycle

   • (c) Less than that of Otto cycle

   • (d) None

ANS: ©

5. The efficiency of Otto cycle can be increased by

   • (a) Increasing the compression ratio

   • (b) Decreasing the compression ratio

   • (c) By increasing as well as by decreasing the compression ratio

   • (d) None

ANS: (b)

6. Compression ratio in an Otto cycle is

   • (a) Stroke volume/clearance volume

   • (b) Total cylinder volume/stroke volume

   • (c) Total cylinder volume/clearance volume

   • (d) None

ANS: (d)

7. Gas constant is

   • (a) Molecular mass /Molecular volume

   • (b) Molecular mass/Universal gas constant

   • (c) Molecular mass x molecular volume

   • (d) None

ANS: (d)

8. Efficiency of Otto cycle is given by

   • (a) η = 1—1/r^γ

   • (b) η = 1—1/r^γ+1

   • (c) η = 1—1/r^γ-1

   • (d) None

ANS: ©

9. Adiabatic index γ is

   • (a) Greater than poly-tropic index ‘n’

   • (b) Less than the poly-tropic index ‘n’

   • (c) Equal to the poly-tropic index ‘n’

   • (d) None

ANS: (a)

10. The efficiency of Carnot cycle can be increased by

    • (a) Increasing the higher temperature

    • (b) Decreasing the higher temperature

    • (c) Increasing the lower temperature

    • (d) None

ANS: (b)

11. The efficiency of Ericsson cycle is

    • (a) Less than the efficiency of Carnot cycle

    • (b) Greater than the efficiency of Carnot cycle

    • (c) Equal to the efficiency of Carnot cycle

    • (d) None

ANS: ©

12. The efficiency of dual combustion cycle is

    • (a) Greater than the efficiency of the Diesel Cycle

    • (b) Less than the efficiency of diesel cycle

    • (c) Equal to the efficiency of diesel cycle

    • (d) None

ANS: (a)

13. The efficiency of dual combustion cycle is

    • (a) Greater than the efficiency of the Otto Cycle

    • (b) Less than the efficiency of Otto cycle

    • (c) Equal to the efficiency of Otto cycle

    • (d) None

ANS: (b)

14. Compression ratio is much higher for a

    • (a) Otto Cycle

    • (b) Diesel cycle

    • (c) Dual cycle

    • (d) None

ANS: (b)

15. The efficiency of a Carnot Cycle working between the limits of 127 and 27⁰C is

    • (a)0. 25

    • (b) 0.75

    • (c) 0.50

    • (d) None

ANS: (b)

16. Mean effective pressure is equal to

    • (a) Work done x stroke volume

    • (b) Stroke volume/work done

    • (c) Work done –stroke volume

    • (d) None

ANS: (d)

17. One working stroke is completed in a four stroke cycle in

    • (a) One revolution

    • (b) Three revolutions

    • (c) Five revolutions

    • (d) None

ANS: (d)

18. Heat added during constant volume process in an air cycle is

    • (a) m c_p (t₂—t₁)

    • (b) m(h₂—h₁)

    • (c) m(u₂—u₁)

    • (d) None

ANS: ©

19. A cycle consisting of two isobaric and two isen-tropic processes is a

    • (a) Sterling Cycle

    • (b) Carnot cycle

    • (c) Brayton cycle

    • (d) None

ANS: (c)

20. Diesel cycle is used where power requirements are

    • (a) Less

    • (b) Heavy

    • (c) Normal

    • (d) None

ANS: (b)

21. The efficiency of an Otto cycle is a function of

    • (a) Only high and low pressures

    • (b) Only high and low temperatures

    • (c) Both high pressure and high temperature

    • (d) None

ANS: (d)

 

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