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. A 1 mole ideal gas expands isothermally at 400 K from volume 5 L to 10 L. Calculate entropy change. (Take )

2. Which of the following is not a mechanism of heat transfer?

3. One mole of an ideal gas expands isothermally from 2 L to 10 L at 300 K. Calculate the entropy change. (Take )

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

5. Which refrigerant was widely used in older air conditioners but phased out due to ozone depletion?

6. A gas expands adiabatically and does of work. What is the change in internal energy?

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

8. Which heat transfer process is primarily responsible for sea and land breezes?

9. When ice melts at 0°C, what happens to entropy? (Latent heat of fusion = 334 J/g).

10. Which factor must be avoided to ensure accurate calibration of thermometers?

11. The molar heat capacity at constant volume is related to specific heat by:

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

13. The Carnot theorem states that:

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

15. Which of the following devices would violate the Second Law if possible?

16. A Carnot engine works between 800 K and 400 K. Its efficiency is:

17. The ideal gas law is expressed as:

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

19. A gas at has pressure . If temperature is increased to at constant volume, what will be the final pressure?

20. Which statement about reversibility is correct?

21. Which among the following is not a state variable?

22. Which modern technology improves the efficiency of air conditioners and climate control systems?

23. Which of the following is an isolated system?

24. The evaporator in a refrigerator works as:

25. A 0.1 kg piece of iron at is placed in 0.2 kg water at . If and , the final equilibrium temperature is:

26. One mole of a diatomic ideal gas () is compressed adiabatically from 10 L at 300 K to 5 L. Find the final temperature.

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

28. A container of 2 moles of ideal gas expands at constant pressure of from 0.01 m³ to 0.02 m³. Calculate the work done by the gas.

29. A steam turbine in a thermal power plant produces 2000 kJ of work while receiving 5000 kJ of heat from the boiler. Calculate its efficiency.

30. In a TS diagram, the area under the curve represents:

1. The work output of a Carnot cycle is equal to:

2. Which of the following phenomena illustrates the Second Law?

3. Maxwell’s relation expresses relationship between:

4. Which of the following is an example of a reversible process?

5. The Third Law of Thermodynamics states that:

6. A gas undergoes a reversible adiabatic compression from volume 4 L to 1 L. The entropy change is:

7. In a cyclic process, the system returns to its initial state. What is the change in internal energy after one cycle?

8. One mole of an ideal gas expands isothermally at 400 K from 2 L to 20 L. Calculate the work done and entropy change. (Take ).

9. Why is the Carnot cycle not practically achievable?

10. A gas initially at pressure , volume , and temperature . If it changes to pressure , volume , temperature , which of the following remains unchanged?

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

12. Work in thermodynamics is defined as:

13. The Carnot cycle is based on which principle?

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

15. In an isothermal expansion of an ideal gas, the work done is given by:

16. A system absorbs 500 J of heat and does no work. What is the change in internal energy?

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

18. Which property is NOT a thermodynamic state variable?

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

20. The entropy of an isolated system:

21. Which thermodynamic cycle is the basis of most steam power plants?

22. Why is the ideal gas law often used in preliminary thermodynamic analysis instead of the Van der Waals equation?

23. The efficiency of a heat engine is given by:

24. Which statement best summarizes the applications of Carnot efficiency?

25. A real steam turbine has an efficiency of 35% while the Carnot efficiency between its temperature limits is 60%. What does this indicate?

26. Entropy is best described as:

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

28. A system undergoes adiabatic compression. What happens to its temperature?

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

30. A Carnot refrigerator works between 250 K and 300 K. Find its maximum COP.

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

32. 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.

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

34. The role of entropy in energy conversion can be summarized as:

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

36. In convection, heat transfer occurs due to:

37. The SI unit of internal energy is:

38. How does the Zeroth Law ensure consistency in temperature measurement?

39. 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 ).

40. Why is Carnot’s theorem important in thermodynamic analysis?

41. Which of the following is correct for an isothermal process involving an ideal gas?

42. The maximum efficiency of a heat engine operating between and is:

43. A 1 mole ideal gas expands isothermally at 400 K from volume 5 L to 10 L. Calculate entropy change. (Take )

44. A hot cup of tea placed in a cooler room eventually cools down. When does thermal equilibrium occur?

45. Which among the following is not a state variable?

46. A Carnot heat pump operates between 300 K (inside room) and 270 K (outside). Calculate its maximum COP.

47. Which heat transfer process is primarily responsible for sea and land breezes?

48. A Carnot engine takes in 1000 J of heat at 500 K and rejects heat at 300 K. Calculate the work output.

49. 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.

50. Carnot’s theorem states that: