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

2. A refrigerator absorbs 600 J of heat from the cold space and rejects 800 J to the surroundings. Find its COP.

3. For an ideal gas, the ratio of specific heats is defined as:

4. Which of the following processes is practically irreversible?

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

6. In an adiabatic process, according to the First Law:

7. A heat pump requires 500 J of work to deliver 2000 J of heat to the room. What is its COP?

8. In an isochoric process, the heat supplied is:

9. The practical implication of entropy increase in real thermodynamic systems is:

10. The amount of heat required to raise the temperature of a body is calculated using:

11. A metal rod of length 1 m and cross-sectional area has thermal conductivity . If its ends are maintained at and , the rate of heat conduction is:

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

13. In refrigeration systems, entropy analysis helps to:

14. Which instrument operates on the principle of thermal equilibrium?

15. A gas expands isothermally from 2 L to 6 L against a piston. If expansion is done reversibly, the work done is:

16. 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:

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

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

19. 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?

20. The Celsius scale is calibrated such that:

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

22. A black body at 300 K emits radiation energy at a rate of . If its temperature is doubled, the emission rate becomes approximately:

23. Which of the following factors reduces efficiency of real thermodynamic systems?

24. Convert normal human body temperature into Celsius.

25. A heat engine absorbs of heat from a source and rejects to the sink. What is the work output?

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

27. Which condition ensures accurate temperature measurement using a thermometer?

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

29. A Carnot engine absorbs 1000 J of heat from a reservoir at 600 K and rejects heat to a sink at 300 K. How much work is produced?

30. In convection, heat transfer occurs due to:

1. Entropy change for mixing two different ideal gases is:

2. For thermal equilibrium to be established, the heat transfer must continue until:

3. In refrigeration systems, entropy analysis helps to:

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

5. Why is the Zeroth Law essential for using thermometers in daily life?

6. A calorimeter contains 250 g of water at . A 100 g piece of metal at is placed in it. Final equilibrium temperature is . Find the specific heat of the metal. (Specific heat of water = ).

7. Why is the Carnot engine considered idealized?

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

9. Which principle is the basis of calorimetry?

10. A Carnot engine works between a hot reservoir at 900 K and a cold reservoir at 300 K. If it absorbs 1800 J of heat, how much heat is rejected?

11. The Brayton cycle is used in:

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

13. Why is entropy important in heat transfer processes?

14. 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.

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

16. A 500 g block of aluminum at is mixed with 200 g of water at . If and , calculate the final equilibrium temperature.

17. Which equation represents conservation of energy in the First Law of Thermodynamics?

18. The concept of reversibility in thermodynamics refers to:

19. In an air conditioning system, the evaporator coil is responsible for:

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

21. Which of the following situations involves an increase in entropy?

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

23. A system absorbs 1200 J of heat reversibly at a constant temperature of 300 K. Calculate the change in entropy.

24. In a hydroelectric power plant, which conversion of energy occurs?

25. Two objects in thermal contact are said to be in equilibrium when:

26. The Boltzmann constant has the value:

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

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

29. Which of the following is the reversibility criterion for a thermodynamic process?

30. A clinical thermometer is designed to measure human body temperature accurately because:

31. A resistance thermometer works on the principle that:

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

33. If body A is in thermal equilibrium with body B, and body B with body C, then which parameter is the same for all three according to the Zeroth Law?

34. A refrigerator removes of heat from its cold compartment and rejects of heat to the surroundings. How much work input is required?

35. Entropy change for an ideal gas in terms of and is:

36. A gas expands from 1 L to 3 L against a constant external pressure of . Calculate the work done by the gas. (Take ).

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

38. Internal energy of an ideal monoatomic gas is given by:

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

40. A gas undergoes an isothermal expansion from 2 L to 8 L at 300 K. Calculate the heat absorbed if 1 mole of the gas is used. (Take ).

41. In thermodynamics, which of the following is a path function?

42. The significance of the Carnot engine in thermodynamics is that:

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

44. If two Carnot engines operate between the same reservoirs, then:

45. Which of the following is a correct statement about entropy change in an isolated system according to the Second Law?

46. The evaporator in a refrigerator works as:

47. In large buildings, centralized cooling systems often use:

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

49. Which of the following processes is practically irreversible?

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