Thermodynamics Mock Test – Class 11 Physics

1. In a piston-cylinder system, the gas pressure is , and the piston moves outward so that the volume increases by at approximately constant pressure. The work done by the gas is

2. For a fixed amount of ideal gas heated at constant pressure from to , its volume

3. A derivation note is shown below.

Using the first law , the note leads to

4. The derivation of for an ideal gas uses the fact that constant-pressure expansion work for a temperature change is

5. A gas is heated at constant volume and receives of heat. What is the change in internal energy?

6. A note says, “Since , its value can be used without specifying the kind of gas or the model.” The best correction is:

7. A closed system receives of heat. Its internal energy increases by . What work is done by the system?

8. A gas loses of heat to the surroundings while of work is done on the gas. Using , find .

9. A heat pump supplies heat to a warm room by taking heat from a cold outside region and using work . Its coefficient of performance as a heat pump is

10. A heat engine operating between and rejects of heat per cycle. If it were Carnot, the heat absorbed would be

11. A refrigerator and a heat pump operate reversibly between the same two reservoirs and , where . If the refrigerator coefficient of performance is and heat-pump coefficient of performance is , then

12. A thermometer is first placed in a beaker of water and later in an oil bath. In both cases, the final steady reading is . What would happen if the water and oil were brought into thermal contact under these conditions?

13. A substance has specific heat capacity and molar mass . Its molar heat capacity for the same process is

14. An ideal gas with and expands adiabatically from to . The work done by the gas is

15. A reversible heat pump works between outside and inside. If it delivers of heat to the room, the work input and heat taken from outside are respectively

16. Use the graph description below.

The graph mainly represents that

17. Use the graph description below.

If the process has molar heat capacity , the slope of the graph is

18. A refrigerator removes of heat from its cold chamber in one cycle and requires of work input. Its coefficient of performance is

19. A gas does of work while its internal energy decreases by . The heat for the process is

20. Assertion: A quasistatic process can be represented by a smooth path on a - diagram.
Reason: The system has well-defined thermodynamic variables at each stage of a quasistatic process.

21. A reversible adiabatic expansion of an ideal gas has , , and . The final temperature is

22. An adiabatic compression raises the temperature of of an ideal gas from to . If , the work done by the gas is

23. For a reversible adiabatic process of an ideal gas, a useful temperature-volume relation is

24. A gas is heated at constant pressure, and its temperature rises. The relation for gases is mainly because

25. A process has and . Using , the change in internal energy is

26. Thermodynamics is most directly concerned with the relation among which physical ideas?

27. A ideal gas at expands isothermally from to , then is compressed adiabatically back to volume . If , , and , the net work done by the gas over the two steps is closest to

28. A cyclic device takes from a cold body and rejects to a hot body. The most suitable interpretation is

29. A gas is taken through the following two-step process: Step P is isochoric heating from to , and Step Q is isothermal expansion at . For the whole two-step process, the internal-energy change of the ideal gas is determined by

30. A proposed engine absorbs from a reservoir at , rejects to a reservoir at , and produces of work. Which judgement is most suitable?

31. Two isothermal expansions of the same ideal gas start at the same temperature. In Case P, the volume changes from to . In Case Q, it changes from to . The ratio of works is

32. No engine operating between the same two reservoirs can be more efficient than a Carnot engine because the Carnot engine is

33. A refrigerator has and removes of heat from the cold chamber in each cycle. The work input required per cycle is

34. A Carnot engine works between and . If a real engine between the same reservoirs claims efficiency, the claim is

35. A gas sample has , , and . Using , the number of moles is

36. Specific heat capacity of a substance is the heat required

37. A full formula check gives the following entries.

The correct entry is

38. A fixed ideal gas is taken through a process in which , , and for of gas. The temperature change is

39. For a Carnot engine, the ratio of heat rejected to heat absorbed is related to reservoir temperatures by

40. A Carnot cycle consists of which sequence of reversible processes?

41. Assertion: A real process involving heat flow through a finite temperature difference is irreversible.
Reason: The reverse transfer from colder body to hotter body would not occur by itself without some additional effect.

42. A gas in a closed vessel is at rest as a whole, but its molecules are moving randomly. The energy connected with this random molecular motion contributes to

43. A Carnot engine is best described as

44. A fixed amount of ideal gas expands isothermally and does of work. Using , the heat supplied to the gas is

45. The SI unit of the gas constant in is obtained as

46. Use the arrangement described below: a gas in a cylinder is compressed once by a rough piston and once by a frictionless piston, both very slowly. The two paths have the same initial and final volumes.
The rough-piston process is less reversible mainly because

47. Study the table and identify the row in which both classifications are correct.

48. A proposed refrigerator removes from a cold chamber and rejects to a hotter room with no work input. The proposal is impossible mainly because

49. Use the arrangement described below: a gas is enclosed in a cylinder with a frictionless movable piston. In Case 1, the piston is moved outward very slowly by reducing the external pressure in tiny steps. In Case 2, the piston is suddenly released against a much lower external pressure. The better comparison is

50. A smooth - curve is normally drawn for a quasistatic process because