Thermodynamics Mock Test – Class 11 Physics

1. A Carnot engine operates between and . Its efficiency is

2. A fixed amount of ideal gas goes from state P to state Q through two different paths. In both cases, the initial and final temperatures are and . What can be said about ?

3. A gas in a container has molecules moving randomly at high speeds, yet a pressure gauge attached to the container shows one steady reading. This situation illustrates that

4. Consider the following statements about thermodynamic equilibrium.
I. Thermal equilibrium requires no temperature gradient.
II. Mechanical equilibrium requires no unbalanced pressure difference causing macroscopic motion.
III. Complete thermodynamic equilibrium can exist even while the system is undergoing a visible chemical reaction.

5. A reversible adiabatic ideal-gas process is represented on a - graph. If the graph is compared with an isothermal curve through the same point, the adiabatic curve is steeper because the pressure varies as

6. Assertion: A reversible thermodynamic process is an idealization.
Reason: Real processes usually involve effects such as friction, finite temperature difference, turbulence, or uncontrolled expansion.

7. The macroscopic viewpoint in thermodynamics mainly uses quantities such as

8. A heat engine has efficiency and rejects to the sink in each cycle. The heat absorbed from the source is

9. A Carnot engine absorbs of heat from a reservoir at and rejects heat to a reservoir at . The heat rejected is

10. A Carnot refrigerator works between and . Its coefficient of performance is

11. Read the passage and answer the question.

What must be the same for the two processes?

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 fixed ideal gas has the same initial and final temperatures in two processes. Process P is isothermal expansion. Process Q is free expansion in an insulated rigid container. The correct comparison is

14. A gas is compressed in a cylinder, and at the same time of heat leaves it. If of work is done on the gas, what is using ?

15. A gas in a piston-cylinder arrangement is compressed very slowly, but heat is allowed to flow out through a finite temperature difference with the surroundings. The process is not fully reversible because

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

17. Use the graph description below.

The graph mainly represents that

18. A gas expands at constant pressure from to . During the process, its internal energy increases by . The heat supplied is

19. A thermodynamic process is reversible only if both the system and surroundings can be restored to their initial states. Which situation most clearly prevents this?

20. The second law explains why a heat engine must reject some heat to a sink. This rejected heat is necessary because

21. A gas sample is heated by once at constant volume and once at constant pressure. The heat required is not generally the same in the two cases because

22. In the equation , the equivalent expression for is

23. A fixed amount of ideal gas is taken through a cycle consisting of an isobaric expansion, an isochoric cooling, and a return path. Over the complete cycle, the internal energy change is

24. A gas at constant volume receives heat . A note says, “Since the gas has pressure, some of must become expansion work.” The best correction is:

25. A graph is described below.

The graph is

26. A process record says: , , and the gas is ideal with . The temperature change of the gas is

27. Study the classification table and identify the row that gives the most suitable example.

28. A gas receives of heat while expanding against a constant pressure of . Its volume increases by . The change in internal energy is

29. Study the table and identify the row with the most accurate classification.

30. A Carnot refrigerator operates between a cold reservoir at and a hot reservoir at , where . Its coefficient of performance is

31. Match the isothermal ideal-gas situation with the correct sign result.

32. A proposed engine between and has efficiency . The proposal is best judged as

33. A gas absorbs of heat and does of work on the surroundings. Using , what is ?

34. In a - diagram, two curves pass through the same point for a fixed ideal gas: an isothermal curve and a reversible adiabatic curve. At that point, the adiabatic curve is steeper because

35. A full formula check gives the following entries.

The correct entry is

36. A Carnot engine rejects of heat to a reservoir at . It operates with a hot reservoir at . The heat absorbed from the hot reservoir is

37. A claim says, “An ideal gas expands isothermally, so no heat enters the gas.” The best correction is:

38. For an ideal gas, a change in internal energy is most directly linked with a change in

39. Two metal blocks are kept in thermal contact for a long time inside an insulated box. No net heat flows between them after some time. The blocks are then said to be in

40. A sample is doubled by adding an identical sample at the same pressure and temperature. Which set shows the variables that double?

41. A student writes for an adiabatic compression because the gas volume changes. The main error is that

42. A compact comparison of four processes is given below.

Which set of entries is correct?

43. A statement says, “The heat of a gas at a state is .” The main problem with this statement is that

44. A fixed amount of gas is enclosed in a cylinder fitted with a movable piston. For the gas as the system, the piston and outside air are part of the

45. 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.

46. A heat engine and a refrigerator are operated between the same two reservoirs. The heat engine delivers work, and that work is used to run the refrigerator. If the two devices together produce no net change in the reservoirs, what does this suggest about the two devices?

47. 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

48. Read the situation below.

The most suitable description of the energy transfers is:

49. A complete thermodynamics summary table is being checked. Which row contains only correct associations?

50. A device works in a cycle between two reservoirs. It takes heat from a colder region, rejects heat to a hotter region, and requires external work input. This device is best described as