ENTROPY OF STEAM MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

ENTROPY OF STEAM

MULTIPLE CHOICE QUESTIONS

(MCQ) WITH ANSWERS 

 

Entropy is randomness. More is the

randomness, more is the entropy. Every

process in nature is ir-reversible. An ir-

reversible process increases entropy.

Increase of entropy means capacity

to do useful work decreases.

  1. Entropy of water is zero at

  • (a) -400C

  • (b) -200C

  • (c) +400C

  • (d) None

ANS: (d)

  1. Change of entropy from temperature t1 to t2 is given by

(a) ∫ds =∫ cp dT/T

(b)∫ ds = ∫cv dT/T

(c) ∫ds = ∫(cp dT/T + cv dT/T)

(d) None

ANS: (a)

  1. Entropy of wet steam is equal to

    • (a) sl + sv

    • (b) sl + x sv

    • (c) sl + x hfg

    • (d) None

ANS: (d)

  1. Entropy of wet steam is equal to

    • (a) sl + x sv/T

    • (b) (1-x) sl + x sv

    • (c) sl + x hfg T

    • (d) None

ANS: (b)

  1. Entropy of dry saturated steam is equal to

    • (a) sl + sv

    • (b) sv — sl

    • (c) sl + sfg

    • (d) None

ANS: ©

  1. Entropy of super heated steam is equal to

    • (a) sl + sv( T super –T sat)

    • (b) sl + Cpsv

    • (c) sv + cpln(Tsup/Tsat)

    • (d) None

ANS: ©

  1. Increase in entropy per 0C is more for a

    • (a) Liquid

    • (b) Saturated vapor

    • (c) Super heated vapor

    • (d) None

ANS: (a)

  1. During a iso-thermal evaporation process, entropy

  • (a) Increases

  • (b) Decreases

  • (c) Remains same

  • (d) None

ANS: (a)

  1. During a iso-thermal condensation process, entropy

  • (a) Increases

  • (b) Decreases

  • (c) Remains same

  • (d) None

ANS: (b)

  1. When water is heated from 00C to 1000C, entropy

is given by

  • (a) cp ln(273)

  • (b) cp ln(373)

  • (c) cp ln(T/273)

  • (d) None

ANS: (d)

  1. On the enthalpy entropy diagram, constant entropy line will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (b)

  1. On the temperature entropy diagram, Constant pressure line will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (c)

  1. On the pressure enthalpy diagram, constant entropy line will be a

    • (a)Horizontal line

    • (b)Vertical line

    • (c) Inclined line

    • (d) None

ANS: (c)

  1. The throttling process on a enthalpy entropy diagram will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (b)

  1. Temperature used in calculation of entropy is

    • (a) 0C

    • (b) K

    • (c) 0C OR K

    • (d) None

ANS: (b)

  1. Heating of water from 00C to 1000C on the temperature entropy diagram will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (c)

  1. Evaporation of water at 1000C on the T-s diagram will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (a)

  1. Super heating of steam on the T-s diagram will be a

    • (a) Horizontal line

    • (b) Vertical line

    • (c) Inclined line

    • (d) None

ANS: (c)

  1. Which one is the Mollier chart for steam

    • (a) P–V diagram

    • (b) P–h diagram

    • (c) h–s diagram

    • (d) None

ANS: ©

  1. The entropy of water at 900C will be

    • (a) 1195 kJ/kg

    • (b) 119.5 kJ/kg

    • (c) 1.195 kJ/kg

    • (d) None

ANS: ©

21. Change in entropy change is directly proportional to the

    1. Temperature

    2. Enthalpy

    3. Internal energy

    4. None

ANS: (iv)

22. Entropy of a system increases with the

    1. Rise of temperature

    2. Fall of temperature

    3. Rise as well fall of temperature

    4. None

ANS: (i)

23. Absolute value of entropy can be found with the help of

    1. Enthalpy

    2. Internal energy

    3. Specific heat

    4. None

ANS: (iv)

24. Datum for entropy is

    1. O 0 C

    2. O 0 F

    3. 0 K

    4. None

ANS (iv)

25. Datum for entropy is

    1. -40 0 C

    2. -4O 0 F

    3. -40 K

    4. None

ANS: (i)

26. Entropy reduces for each degree oC by

    1. 1/10

    2. 1/20

    3. 1/30

    4. None

ANS: (iv)

27. For each degree oC fall of temperature, entropy decreases by

    1. 1/73

    2. 1/173

    3. 1/273

    4. None

ANS: (iii)

28. In any real process, entropy always

    1. Decreases

    2. Increases

    3. Remains constant

    4. None

ANS: (ii)

29. During an iso-baric process, entropy

    1. Decreases

    2. Increases

    3. Remains constant

    4. None

ANS: (ii)

30. During an iso-metric process, entropy

    1. Increases

    2. Decreases

    3. Remains constant

    4. None

ANS: (i)

31. During an isen-tropic process, entropy

    1. Decreases

    2. Increases

    3. Remains constant

    4. None

ANS: (iii)

32. During an adiabatic process, entropy

    1. Decreases

    2. Increases

    3. Remains constant

    4. None

ANS: (ii)

33. During an isenthalpic process, entropy

    1. Decreases

    2. Increases

    3. Remains constant

    4. None

ANS: (ii)

34. During an constant internal energy process, entropy

    1. Increases

    2. Decreases

    3. Remains constant

    4. None

ANS: (i)

35. Datum is a reference level for zero values of

    1. Volume and entropy

    2. Volume and enthalpy

    3. Entropy and enthalpy

    4. None

ANS: (iii)

36. What is the datum for zero enthalpy in S.I. Units

    1. 0oC

    2. 0oF

    3. 0 K

    4. None

ANS: (iv)

37. What is the datum for zero enthalpy in S.I. Units

    1. 0oC

    2. -20oC

    3. -40oC

    4. None

ANS: (iii)

38. What is symbol for specific entropy

    1. S

    2. s

    3. ds

    4. None

ANS: (ii)

39. What is symbol for total entropy

    1. S

    2. s

    3. ds

    4. None

ANS: (i)

40. What is the unit of specific entropy in S.I. Units

    1. J/kg

    2. kJ/kg

    3. J/g

    4. None

ANS: (iv)

41. What is the unit of specific entropy in S.I. Units

    1. J/kg o C

    2. kJ/kg o C

    3. J/g o C

    4. None

ANS: (ii)

42. What is the unit of total entropy in S.I. Units

    1. J/kg o C

    2. kJ/ o C

    3. J/g o C

    4. None

ANS: (ii)

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