Thermodynamics Mock Test – Class 11 Physics

1. A gas is cooled at constant volume, and of heat leaves the gas. Using , the work done by the gas and the change in internal energy are respectively

2. A thermodynamic state variable is a quantity that

3. Read the situation below.

During the approach to equilibrium, the heat transfer depends directly on

4. A gas process has a smooth - path only when each intermediate state can be assigned well-defined thermodynamic variables. This requirement is most closely connected with

5. A claim says, “For a Carnot engine, efficiency depends on the working substance.” The best correction is:

6. A fixed mass of gas has density , mass , and volume . Its density is written as . If the gas reaches the same final state through two paths, the final density is

7. Use the arrangement described below: a gas in equilibrium is represented by a point on a - diagram. The same gas is then suddenly compressed so violently that pressure is not uniform inside it for a short time. During that short interval, a single point on the - diagram is unreliable because

8. Assertion: For a gas, is usually greater than .
Reason: For gases, because constant-pressure heating includes expansion work.

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

10. A ideal gas at is first heated at constant volume until its pressure doubles. It then expands reversibly and adiabatically until its temperature returns to . If , the work done by the gas in the adiabatic step is

11. Consider the following statements about thermodynamic systems.
I. The surroundings mean everything outside the chosen system.
II. A closed system can exchange energy but not matter with its surroundings.
III. An isolated system must exchange matter but not heat.

12. A gas suddenly expands into an evacuated chamber. This process is usually classified as irreversible mainly because

13. A hot body and a cold body are separated by a conducting wall. Net heat flow stops only when

14. The coefficient of performance of a refrigerator is defined as

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

16. A container has of gas in equilibrium at pressure , temperature , volume , and internal energy . It is divided into two equal parts, each containing , without changing the equilibrium temperature. For each half, the most suitable comparison is

17. In the equation , the equivalent expression for is

18. A gas undergoes a slow isothermal expansion while kept in contact with a large heat reservoir. The role of the reservoir is mainly to

19. In a Carnot engine, heat is absorbed from the hot reservoir during

20. For a gas heated at constant pressure, the heat supplied is used to

21. A final error-check table for thermodynamics gives four claims. Which claim is correct?

22. Consider the following statements about heat capacities.
I. is specific heat capacity.
II. is molar heat capacity.
III. The unit of is .

23. A Carnot engine operates between and . Another engine between the same reservoirs has the same heat input but produces less work. The most suitable conclusion is that the second engine

24. A Carnot engine is best described as

25. In an isobaric expansion, the rectangular area under the horizontal line on a - graph equals

26. A cyclic engine absorbs from a source and rejects to a sink, where and are positive magnitudes. The work output is

27. Internal energy of a gas refers mainly to

28. A ideal gas follows a two-step path. First, it expands isothermally at from to . Second, it is heated at constant volume from to . If , , and , the total change in internal energy and total work done by the gas are respectively

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

30. A claim says, “Since heat changes the temperature of a gas, heat must be a state variable like .” The best correction is:

31. 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

32. The same rectangular - loop is traversed once clockwise and once anticlockwise. The magnitude of enclosed area is . The net work done by the gas in the anticlockwise cycle is

33. A gas is compressed inside a thermally insulated cylinder. If of work is done on the gas, the change in internal energy is

34. A gas initially has a pressure difference between two regions inside the same container. After some time, the pressure becomes uniform and there is no bulk motion. This change mainly shows approach toward

35. A metal block at is placed in contact with another block at . Before thermal equilibrium is reached, heat transfer is mainly from

36. For isothermal expansion of a fixed amount of ideal gas from to , the work done by the gas is

37. 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

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

39. A student compares two Carnot engines. Engine P works between and . Engine Q works between and . The correct comparison is

40. An extensive variable is a thermodynamic quantity that

41. The Clausius statement of the second law says that

42. Assertion: A positive value of always means heat is supplied to the chosen system.
Reason: The sign of heat depends on the direction in which energy crosses the system boundary.

43. A Carnot engine absorbs from and rejects heat to . Its work output drives a refrigerator with COP . If the refrigerator removes from its cold chamber, the heat absorbed by the engine must be

44. Read the situation below and answer the question.

The work delivered per cycle is

45. A microscopic description of a gas would be most concerned with

46. Match the quantity with its correct thermodynamic nature.

47. For a fixed amount of ideal gas, match the condition with the relation that follows from .

48. For a fixed amount of ideal gas undergoing an isothermal process, the change in internal energy is zero because

49. A ideal gas expands isothermally at from volume to . Taking and , the work done by the gas is closest to

50. Use the graph description below.

At the same larger volume, the adiabatic curve lies