Thermodynamics
21. An adiabatic wall is one which
- prevents thermal interaction
- permits thermal interaction
- encourages thermal interaction
- discourages thermal interaction
- dos not exist.
Correct answer: (A)
prevents thermal interaction
22. An engine operates between temperatures of 900°Kandr2 and another engine between T2 and 400°K For both to do equal work, value of T2 will be
- 650°K
- 600°K
- 625°K
- 700°K
- 750°K.
23. An ideal gas as compared to a real gas at very high pressure occupies
- more volume
- less volume
- same volume
- unpredictable behaviour
- no such correlation.
Correct answer: (A)
more volume
24. An isolated system is one in which
- mass does not cross boundaries of the system, though energy may do so
- neither mass nor energy crosses the boundaries of the system
- both energy and mass cross the boundaries of the system
- mass crosses the boundary but not the energy
- thermodynamic reactions do not occur.
Correct answer: (B)
neither mass nor energy crosses the boundaries of the system
25. An open system is one in which
- mass does not cross boundaries of the system, though energy may do so
- neither mass nor energy crosses the boundaries of the system
- both energy and mass cross the boundaries of the system
- mass crosses the boundary but not the energy
- thermodynamic reactions do not occur.
Correct answer: (C)
both energy and mass cross the boundaries of the system
26. Barometric pressure is equal to
- 760 mm Hg
- zero mm Hg
- 735.6 mm Hg
- 1 mm Hg
- 100mm Hg.
Correct answer: (A)
760 mm Hg
27. Boyle's law i.e. pV = constant is applicable to gases under
- all ranges of pressures
- only small range of pressures
- high range of pressures
- steady change of pressures
- atmospheric conditions.
Correct answer: (B)
only small range of pressures
28. Brayton cycle consists' of following four processes
- two isothermals and two isentropics
- two isentropics and two constant volumes
- two isentropics, one constant volume and one constant pressure
- two isentropics and two constant pres-sures
- none of the above.
Correct answer: (D)
two isentropics and two constant pres-sures
29. Calorie is a measure of
- specific heat
- quantity of heat
- thermal capacity
- entropy
- work.
Correct answer: (B)
quantity of heat
30. Carnot cycle efficiency depends upon
- properties of the medium/substance used
- condition of engine
- working condition
- temperature range of operation
- effectiveness of insulating material around the engine.
Correct answer: (D)
temperature range of operation