Thermodynamics

51. For which of the following substances, the internal energy and enthalpy are the functions of temperature only

  1. any gas
  2. saturated steam
  3. water
  4. perfect gas
  5. superheated steam.

Correct answer: (D)
perfect gas

52. Gas turbine cycle consists of

  1. two isothermals and two isentropics
  2. two isentropics and two constant volumes
  3. two isentropics, one constant volume and one constant pressure
  4. two isentropics and two constant pressures
  5. none of the above.

Correct answer: (D)
two isentropics and two constant pressures

53. Gases have

  1. only one value of specific heat
  2. two values of specific heat
  3. three values of specific heat
  4. no value of specific heat
  5. under some conditions one value and sometimes two values of specific heat.

Correct answer: (B)
two values of specific heat

54. General gas equation is

  1. PV=nRT
  2. PV=mRT
  3. PV = C
  4. PV=KiRT
  5. Cp-Cv = Wj

Correct answer: (B)
PV=mRT

55. Heat and work are

  1. point functions
  2. system properties
  3. path functions
  4. intensive properties
  5. extensive properties.

Correct answer: (C)
path functions

56. I kgf/cm2 is equal to

  1. 760 mm Hg
  2. zero mm Hg
  3. 735.6 mm Hg
  4. 1 mm Hg
  5. lOOmmHg.

Correct answer: (C)
735.6 mm Hg

57. If a certain amount of dry ice is mixed with same amount of water at 80°C, the final temperature of mixture will be

  1. 80°C
  2. 0°C
  3. 40°C
  4. 20°C
  5. 60°C.

Correct answer: (B)
0°C

58. If a fluid expands suddenly into vacuum through an orifice of large dimension, then such a process is called

  1. free expansion
  2. hyperbolic expansion
  3. adiabatic expansion
  4. parabolic expansion
  5. throttling.

Correct answer: (A)
free expansion

59. If a gas is heated against a pressure, keeping the volume constant, then work done will be equal to

  1. =+ v
  2. =- ve
  3. zero
  4. pressure x volume
  5. any where between zero and infinity.

Correct answer: (C)
zero

60. If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as

  1. free expansion
  2. hyperbolic expansion
  3. adiabatic expansion
  4. parabolic expansion
  5. throttling.

Correct answer: (E)
throttling.

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