Class 11 Physics — Chapter 12: Thermodynamics Online Test

1. The relation is called:

2. Maxwell’s relation expresses relationship between:

3. The entropy change of surroundings during a reversible adiabatic process is:

4. Why can no real engine achieve Carnot efficiency?

5. A heat engine absorbs 2000 J of heat at 500 K and rejects 1500 J at 300 K. Does it violate the Second Law?

6. If a refrigerator has a COP of 4, what does it mean?

7. The Brayton cycle is used in:

8. The constant in Van der Waals equation accounts for:

9. A 100 g piece of steam at is passed into 500 g of water at . Find the final temperature when equilibrium is reached. (Latent heat of vaporization = , ).

10. A heat engine absorbs from a source at and rejects to the sink. Find its efficiency.

11. A system absorbs of heat and performs of work. Which statement is correct?

12. Which law of thermodynamics introduces the concept of temperature?

13. Which law of thermodynamics sets the ultimate limit for the efficiency of heat engines?

14. Why is the Zeroth Law significant in thermodynamics?

15. Convert into Kelvin.

16. A system does of work on surroundings and its internal energy decreases by . How much heat was supplied?

17. If a system absorbs of heat and its internal energy increases by , how much work has the system done?

18. Two bodies with masses and , specific heats and , and initial temperatures and , are brought in thermal contact. The final equilibrium temperature is given by:

19. A resistance thermometer works on the principle that:

20. Two objects with heat capacities and are at 500 K and 300 K respectively. What is the final equilibrium temperature?

1. Why are fixed points like the freezing and boiling points of water important in thermometer calibration?

2. A heat engine operates between 1000 K and 400 K, producing 2000 J of work per cycle. Find the minimum heat absorbed.

3. The First Law of Thermodynamics is essentially a statement of:

4. Who gave the First Law of Thermodynamics its modern form?

5. A thermometer placed in thermal contact with a body shows a steady reading after some time. What does this indicate?

6. When an ice cube is placed in a glass of water, the system reaches thermal equilibrium when:

7. For a monoatomic ideal gas, what is the value of ?

8. Two objects with heat capacities and are at 500 K and 300 K respectively. What is the final equilibrium temperature?

9. One mole of an ideal gas is taken from 300 K, 2 atm to 600 K, 4 atm reversibly. Find the entropy change. (Take ).

10. Which of the following fields heavily applies thermodynamic principles?

11. Entropy change of the universe in a reversible process is:

12. A digital thermometer works on the principle of:

13. The statistical definition of entropy was given by:

14. Why can no heat engine have 100% efficiency?

15. The Second Law of Thermodynamics introduces the concept of:

16. A car air conditioning system absorbs 10 kJ of heat per cycle from the passenger cabin and requires 2.5 kJ of work input. Find its COP.

17. In combined-cycle power plants, entropy analysis is used to:

18. The relation connects:

19. A cylinder contains a gas at volume , pressure . If the gas is compressed to at constant temperature, what is the final pressure?

20. Which condition is essential for a thermometer to correctly measure body temperature?

21. Two bodies at different temperatures are brought into thermal contact. Which direction does heat flow initially?

22. A steam turbine receives steam at 500 °C and exhausts it at 40 °C. If Carnot efficiency is 61%, the actual turbine efficiency is usually:

23. Why is Kelvin preferred in scientific thermodynamics over Celsius or Fahrenheit?

24. The Coefficient of Performance (COP) of a refrigerator is defined as:

25. In a TS diagram, the cycle efficiency can be calculated as:

26. A mercury thermometer is placed in hot water at . If the thermometer initially reads , what happens over time?

27. Maxwell’s relation expresses relationship between:

28. The Carnot efficiency depends on:

29. Which thermodynamic device is most directly linked to refrigeration and air conditioning systems?

30. In heat transfer by conduction, thermal conductivity of water compared to metals is:

1. For a reversible adiabatic process of an ideal gas, the relation between temperature and volume is:

2. A Carnot engine works between reservoirs at 800 K and 400 K. If it absorbs 1200 J of heat per cycle, find the work done and heat rejected.

3. Why is calibration of thermometers necessary?

4. A Carnot refrigerator extracts 500 J of heat from a cold reservoir at 270 K and rejects it to a hot reservoir at 300 K. Calculate the work input required.

5. Why are all natural processes considered irreversible?

6. Which of the following is an application of Carnot efficiency in thermodynamic analysis?

7. In a steam engine, the boiler acts as:

8. Why is it necessary to allow sufficient time when using a thermometer?

9. Two objects with heat capacities and are at 500 K and 300 K respectively. What is the final equilibrium temperature?

10. Calculate the molar specific heat at constant volume () for a diatomic ideal gas at room temperature.

11. Convert normal human body temperature into Celsius.

12. A reservoir at 500 K supplies 2000 J of heat to a reversible engine. Calculate the entropy change of the reservoir.

13. Two bodies A and B, with heat capacities and , are initially at and . If they are placed in contact in an isolated system, the final equilibrium temperature is:

14. The Otto cycle is the idealized cycle for:

15. In thermodynamic relationships, entropy is considered useful because:

16. The entropy change when 2 kg of ice at 0 °C melts to water at 0 °C is (latent heat of fusion ).

17. A 1 kg block of iron at is placed in 2 kg of water at . If final temperature is , calculate the specific heat of iron. (Specific heat of water = ).

18. A gas is compressed adiabatically with of work done on it. No heat exchange occurs. What is the change in internal energy?

19. A gas expands isothermally at 300 K from 2 L to 6 L. Calculate the work done by 1 mole of gas. (Take ).

20. An isobaric process on a PV diagram is represented by:

21. In an isothermal process, which parameter remains constant?

22. A heat engine absorbs 2000 J of heat at 500 K and rejects 1500 J at 300 K. Does it violate the Second Law?

23. Which of the following is NOT considered a thermodynamic system?

24. In an internal combustion engine, the hot source is:

25. The basic principle of a heat engine is:

26. A reversible engine rejects 600 J of heat to a sink at 300 K. If its efficiency is 40%, what is the temperature of the source?

27. Which of the following is a path function in thermodynamics?

28. Which of the following processes has zero entropy generation?

29. One mole of an ideal monoatomic gas is heated at constant volume. If its temperature rises from to , calculate the change in internal energy. (Take ).

30. On a PV diagram, which cycle appears as a rectangle?

31. Convert into Kelvin.

32. Which relation is true for a perfect gas?

33. A steam turbine receives steam at 500 °C and exhausts it at 40 °C. If Carnot efficiency is 61%, the actual turbine efficiency is usually:

34. What is the First Law of Thermodynamics also known as?

35. Why is calibration critical in high-precision scientific experiments?

36. Maxwell’s relation expresses relationship between:

37. Heat supplied to a system is always considered positive when:

38. A body of mass 1 kg is thrown vertically upwards with velocity 20 m/s. Ignoring air resistance, what maximum height will it reach? (Take ).

39. Why is the concept of thermal equilibrium important in defining temperature?

40. A piece of iron of mass 500 g at is dropped into 200 g of water at . If and , the equilibrium temperature is closest to:

41. A 2 kg object is dropped from a height of 10 m. Ignoring air resistance, what is its kinetic energy just before hitting the ground? (Take ).

42. A refrigerator extracts of heat from its cold body and requires of work input. What is its coefficient of performance (COP)?

43. In a power cycle, heat supplied is 3000 J and work obtained is 1200 J. Calculate the entropy generated if the source is at 600 K and the sink at 300 K.

44. Two bodies with masses and , specific heats and , and initial temperatures and , are brought in thermal contact. The final equilibrium temperature is given by:

45. A 500 g piece of aluminum () is supplied with of heat. What is the rise in its temperature?

46. Which of the following processes are part of the Carnot cycle?

47. The Boltzmann entropy formula is:

48. A heat engine absorbs of heat and rejects to the sink. Find its efficiency.

49. The Diesel cycle differs from the Otto cycle because:

50. Why are Diesel engines generally more fuel-efficient than petrol engines?