### Thermodynamics

21. An adiabatic wall is one which

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

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

1. 650°K
2. 600°K
3. 625°K
4. 700°K
5. 750°K.

650°K

23. An ideal gas as compared to a real gas at very high pressure occupies

1. more volume
2. less volume
3. same volume
4. unpredictable behaviour
5. no such correlation.

more volume

24. An isolated system is one in which

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

neither mass nor energy crosses the boundaries of the system

25. An open system is one in which

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

both energy and mass cross the boundaries of the system

26. Barometric pressure is equal to

1. 760 mm Hg
2. zero mm Hg
3. 735.6 mm Hg
4. 1 mm Hg
5. 100mm Hg.

760 mm Hg

27. Boyle's law i.e. pV = constant is applicable to gases under

1. all ranges of pressures
2. only small range of pressures
3. high range of pressures
5. atmospheric conditions.

only small range of pressures

28. Brayton cycle consists' of following four processes

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.

two isentropics and two constant pressures

29. Calorie is a measure of

1. specific heat
2. quantity of heat
3. thermal capacity
4. entropy
5. work.

quantity of heat

30. Carnot cycle efficiency depends upon

1. properties of the medium/substance used
2. condition of engine
3. working condition
4. temperature range of operation
5. effectiveness of insulating material around the engine.