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 Carnot engine rejects 1200 J of heat at 300 K and operates with 40% efficiency. Calculate the source temperature.

2. Which mode of heat transfer can occur in vacuum?

3. A gas absorbs of heat and does of work. What is the change in internal energy?

4. Lord Kelvin’s greatest contribution to thermodynamics was:

5. Which physical property equalizes between two systems in thermal equilibrium?

6. Which statement is correct about Carnot efficiency?

7. In practice, why must a heat engine always reject some heat to a sink?

8. Why are all natural processes considered irreversible?

9. A Carnot engine operates between a source at 700 K and a sink at 350 K. Find its efficiency.

10. Which of the following engines is used in nuclear power plants for converting steam energy into electricity?

11. In a reversible isothermal process, the entropy change of an ideal gas is:

12. The specific heat capacity of a substance is defined as:

13. 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:

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

15. Convert normal human body temperature into Celsius.

16. Which of the following is an application of calorimetry in real life?

17. The device that reduces pressure of the refrigerant before entering the evaporator is called:

18. Which of the following is an example of a thermodynamic system?

19. Which 17th-century scientist first hinted at energy conservation through chemical processes?

20. A 200 g block of copper at is placed in 100 g of water at . If the specific heat of copper is and water is , the equilibrium temperature is approximately:

21. If the temperature of the sink in a Carnot engine is lowered, its efficiency will:

22. The efficiency of a Carnot engine operating between and is:

23. A thermometer is placed in a liquid at . After some time, the thermometer reads . What does this indicate according to the Zeroth Law?

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

25. The SI unit of specific heat capacity is:

26. A reversible heat engine absorbs 500 J from a reservoir at 400 K and rejects 300 J to a sink at 300 K. Find the total entropy change of the universe.

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

28. Which of the following correctly converts 0 °C into Fahrenheit?

29. Entropy is related to probability as:

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

1. In climate control systems, why is humidity control important?

2. The basic principle of a heat engine is:

3. A refrigerator extracts 1200 J of heat from the cold space and rejects 1800 J to the surroundings. The work input required is:

4. In a thermal power plant, why is condenser pressure kept very low?

5. The unit “calorie” is defined as:

6. The Carnot cycle efficiency is expressed as:

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

8. A real gas behaves most like an ideal gas under conditions of:

9. Why is the Zeroth Law crucial for building temperature scales like Celsius and Kelvin?

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

11. A 50 g ice cube at is dropped into 200 g of water at . Find the final temperature after thermal equilibrium is reached. (Latent heat of fusion of ice = , specific heat of water = ).

12. Why is the Carnot engine considered idealized?

13. What does thermal equilibrium mean for two bodies in contact?

14. A Carnot engine rejects 1200 J of heat at 300 K and operates with 40% efficiency. Calculate the source temperature.

15. A thermometer placed in boiling water reads 100 °C. Why does it stop rising after reaching that value?

16. The specific heat capacity of a substance is defined as:

17. Which property is NOT a thermodynamic state variable?

18. A steel ball of mass 0.2 kg at is dropped into 0.5 kg water at . If and , the equilibrium temperature is:

19. The working substance in a heat engine is:

20. Which of the following engines is used in nuclear power plants for converting steam energy into electricity?

21. The function of the condenser in a steam engine is:

22. The statistical definition of entropy was given by:

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

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

25. 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 ).

26. In convection, heat transfer occurs due to:

27. A system absorbs of heat and does of work. Calculate the change in internal energy.

28. In a PV diagram, the area under the curve represents:

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

30. Which statement is true for all heat engines?

31. A reversible Carnot engine has efficiency 40% when operating between reservoirs at 500 K and . Find the sink temperature.

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

33. Why is the Zeroth Law significant in thermodynamics?

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

35. Maxwell’s relation expresses relationship between:

36. The Carnot theorem states that:

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

38. Which of the following indicates irreversibility in real processes?

39. 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.

40. Heat in thermodynamics is defined as:

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

42. In practice, why must a heat engine always reject some heat to a sink?

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

44. The principle of conservation of energy states that:

45. Internal energy of a system includes:

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

47. In an isochoric process, the work done is:

48. A heat pump delivers of heat to a room while consuming of work. What is the COP of the heat pump?

49. A gas is compressed such that work of is done on the system and of heat is released by the system. What is the change in internal energy?

50. Why is conservation of energy principle fundamental in physics?