Thermodynamics

1. A closed system is one in which

  1. mass does not cross boundaries of the system, though energy may do so
  2. mass crosses the boundary but not the energy
  3. neither mass nor energy crosses the boundaries of the system
  4. both energy and mass cross the boundaries of the system
  5. thermodynamic reactions take place.

Correct answer: (A)
mass does not cross boundaries of the system, though energy may do so

2. A cycle consisting of two adiabatics and two constant pressure processes is known as

  1. Otto cycle
  2. Ericsson cycle
  3. Joule cycle
  4. Stirling cycle
  5. Atkinson cycle.

Correct answer: (C)
Joule cycle

3. A diathermic wall is one which

  1. prevents thermal interaction
  2. permits thermal interaction
  3. encourages thermal interaction
  4. discourages thermal interaction
  5. does not exist.

Correct answer: (B)
permits thermal interaction

4. A gas is compressed in a cylinder by a movable piston to a volume one-half its original volume. During the process 300 kJ heat left the gas and internal energy remained same. The work done on gas in Nm will be

  1. 300 Nm
  2. 300,000 Nm
  3. 30 Nm
  4. 3000 Nm
  5. 30,000 Nm.

Correct answer: (B)
300,000 Nm

5. A heat exchange process in which the product of pressure and volume remains constant is known as

  1. heat exchange process
  2. throttling process
  3. isentropic process
  4. adiabatic process
  5. hyperbolic process.

Correct answer: (E)
hyperbolic process.

6. A manufacturer claims to have a heat engine capable of developing 20 h.p. by receiving heat input of 400 kcal/mt and working between the temperature limits of 227° C and 27° C. His claim is

  1. justified
  2. not possible
  3. may be possible with lot of sophistications
  4. cost will be very high
  5. theroretically possible.

Correct answer: (B)
not possible

7. A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is

  1. 54°C
  2. 327°C
  3. 108°C
  4. 654°C
  5. 600°C

Correct answer: (B)
327°C

8. A perpetual motion machine is

  1. a thermodynamic machine
  2. a non-thermodynamic machine
  3. a hypothetical machine
  4. a hypothetical machine whose opera-tion would violate the laws of thermodynamics
  5. an inefficient machine.

Correct answer: (D)
a hypothetical machine whose opera-tion would violate the laws of thermodynamics

9. A sudden fall in the barometer reading is a sign of approaching

  1. fine weather
  2. rains
  3. storm
  4. cold wave
  5. hot wave.

Correct answer: (C)
storm

10. Absolute zero pressure will occur

  1. at sea level
  2. at the center of the earth
  3. when molecular momentum of the system becomes zero
  4. under vacuum conditions
  5. at a temperature of - 273 °K

Correct answer: (C)
when molecular momentum of the system becomes zero

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