Hi guys today we are going to solve 50 mcq on the topic thermodynamics. Before going to solve the problem let's revise the topic by some important definition
1. Enthalpy: A thermodynamic property that measures the total energy of a system.
2. Entropy: A thermodynamic property that measures the amount of disorder or randomness in a system.
3. Heat: The transfer of energy between two objects or systems due to a temperature difference.
4. Internal Energy: The total energy contained within a system, including kinetic and potential energy.
5. System: A portion of the universe that is being studied and analyzed in thermodynamics.
6. Surroundings: Everything outside of the system being studied in thermodynamics.
7. Work: The transfer of energy that occurs when a force is applied over a distance.
8. Adiabatic Process: A process where no heat is exchanged between the system and the surroundings.
9. Isobaric Process: A process where the pressure of the system remains constant.
10. Isothermal Process: A process where the temperature of the system remains constant.
11. Carnot Cycle: An idealized thermodynamic cycle that consists of four reversible processes.
12. Heat Engine: A device that converts thermal energy into mechanical energy.
13. Thermal Efficiency: The ratio of the work output of a heat engine to the heat input.
14. Heat Pump: A device that transfers heat from a cooler environment to a warmer environment.
15. Refrigerator: A device that transfers heat from a cooler environment to a warmer environment, but in the opposite direction of a heat pump.
16. Thermodynamic Equilibrium: A state where no net change occurs in a system and its surroundings.
17. Gibbs Free Energy: A thermodynamic property that measures the amount of work that can be extracted from a system.
18. Maxwell's Relations: A set of equations that relate thermodynamic properties to one another.
19. Joule-Thomson Effect: The cooling or heating that occurs when a gas is allowed to expand or contract without doing any work.
20. Clausius-Clapeyron Equation: An equation that relates the vapor pressure of a substance to its temperature and enthalpy of vaporization.
21. First Law of Thermodynamics: Also known as the law of conservation of energy, this law states that energy cannot be created or destroyed, only transferred or converted from one form to another.
22. Second Law of Thermodynamics: This law states that the total entropy (or disorder) of a closed system cannot decrease over time. In other words, energy spontaneously flows from hotter to cooler objects, and it is impossible to convert all heat energy into useful work without producing waste heat.
23. Third Law of Thermodynamics: This law states that as the temperature of a system approaches absolute zero, the entropy of the system approaches a minimum value. This means that at absolute zero, a perfectly ordered state is reached, and all motion of atoms and molecules ceases.
50 multiple choice questions on the topic thermodynamics
1. Which of the following is not a state function in thermodynamics?
a) Enthalpy
b) Entropy
c) Work
d) Internal Energy
2. In which thermodynamic process, the internal energy of the system remains constant?
a) Adiabatic Process
b) Isothermal Process
c) Isochoric Process
d) Isobaric Process
3. The thermodynamic property which tells about the randomness of the system is:
a) Entropy
b) Enthalpy
c) Internal Energy
d) Heat capacity
4. Which law of thermodynamics is related to the concept of absolute zero?
a) Zeroth law
b) First law
c) Second law
d) Third law
5. In which thermodynamic process, the pressure of the system remains constant?
a) Isothermal Process
b) Adiabatic Process
c) Isochoric Process
d) Isobaric Process
6. Which of the following is an extensive property of a thermodynamic system?
a) Density
b) Temperature
c) Pressure
d) Volume
7. Which law of thermodynamics states that it is impossible to convert all the heat into work?
a) Zeroth law
b) First law
c) Second law
d) Third law
8. The efficiency of a Carnot engine depends upon:
a) The temperature of the source and sink
b) The pressure of the source and the sink
c) The volume of the source and the sink
d) The internal energy of the source and the sink
9. The amount of heat required to raise the temperature of a substance is given by its:
a) Enthalpy
b) Internal energy
c) Entropy
d) Heat capacity
10. The process in which the system neither gains nor loses heat from the surroundings is called:
a) Adiabatic Process
b) Isothermal Process
c) Isochoric Process
d) Isobaric Process
11. Which of the following is an intensive property of a thermodynamic system?
a) Mass
b) Volume
c) Temperature
d) Heat capacity
12. The work done in an isobaric process is given by:
a) PΔV
b) nRΔT
c) ΔU
d) ΔH
13. Which law of thermodynamics deals with the conservation of energy?
a) Zeroth law
b) First law
c) Second law
d) Third law
14. The energy stored in the bonds of the molecule is called:
a) Kinetic energy
b) Potential energy
c) Chemical energy
d) Thermal energy
15. Which law of thermodynamics deals with the direction of heat flow?
a) Zeroth law
b) First law
c) Second law
d) Third law
16. Which of the following is not a thermodynamic cycle?
a) Carnot cycle
b) Rankine cycle
c) Otto cycle
d) Boyle's cycle
17. Which law of thermodynamics deals with the concept of entropy?
a) Zeroth law
b) First law
c) Second law
d) Third law
18. The internal energy of a gas is directly proportional to its:
a) Pressure
b) Volume
c) Temperature
d) Mass
19. Which law of thermodynamics deals with the concept of heat flow between two objects?
a) Zeroth law
b) First law
c) Second law
d) Third law
20. The process in which the system neither gains nor loses heat, as well as work, from the surroundings is called:
a) Adiabatic Process
b) isothermal
c) volumetric
d) isochoric
21. The quantity of heat required to convert a solid into a liquid at its melting point is called:
a) Enthalpy of fusion
b) Enthalpy of vaporization
c) Enthalpy of sublimation
d) Enthalpy of reaction
22. In which process, the internal energy of the system increases?
a) Isobaric Process
b) Isothermal Process
c) Adiabatic Process
d) Isochoric Process
23. Which of the following statements is true about an exothermic reaction?
a) It absorbs heat from the surroundings
b) It releases heat to the surroundings
c) It neither absorbs nor releases heat to the surroundings
d) It does not occur spontaneously
24. The entropy of a system can never:
a) Increase
b) Can never Decrease
c) Remain constant
d) Become negative
25. The change in internal energy of a system is equal to:
a) The heat absorbed plus the work done on the system
b) The heat absorbed minus the work done on the system
c) The work done on the system minus the heat absorbed
d) The heat absorbed multiplied by the work done on the system
26. The heat capacity of a system is defined as the amount of heat required to raise its temperature by:
a) 1 degree Celsius
b) 1 J
c) 1 cal
d) 1 eV
27. The change in entropy of a system is given by the formula:
a) ΔG = ΔH - TΔS
b) ΔS = Q/T
c) ΔS = ΔU + ΔH
d) ΔS = PΔV - Q/T
28. Which of the following thermodynamic cycles is used in the operation of a refrigerator?
a) Rankine cycle
b) Carnot cycle
c) Otto cycle
d) Brayton cycle
29. Which of the following is a state function?
a) Enthalpy
b) Work
c) pressure
d) volume
30. The second law of thermodynamics states that the total entropy of an isolated system always:
a) Increases
b) Decreases
c) either increases or remains constant
d) Becomes negative
31. The heat absorbed by a system in a process is equal to the:
a) Change in enthalpy of the system
b) Change in internal energy of the system
c) Change in entropy of the system
d) Work done on the system
32. Which of the following is not a type of thermodynamic system?
a) Closed system
b) Isolated system
c) Open system
d) Ideal system
33. The work done in an isothermal process is given by:
a) nRΔTln(Vf/Vi)
b) ΔU
c) ΔH
d) PΔVln(Vf/Vi)
34. The entropy change of the universe in a spontaneous process is:
a) Positive
b) Negative
c) Zero
d) Cannot be determined
35. In which process, the temperature of the system remains constant?
a) Isobaric Process
b) Adiabatic Process
c) Isothermal Process
d) Isochoric Process
36. The energy required to raise the temperature of a substance from one degree to another is given by its:
a) Enthalpy
b) Internal energy
c) Entropy
d) Specific heat capacity
37. Which of the following is not a unit of entropy?
a) J/K
b) cal/K
c) eV/K
d) J/mol.K
38. The thermodynamic process in which no heat is exchanged with sorrounding
a) adiabatic
b) isochoric
c) isothermal
d) isobaric
39. The reversible process is also known as which of the following?
a) Irreversible process
b) Quasistatic process
c) Adiabatic process
d) Isothermal process
40. The heat capacity at constant volume is given by which of the following?
a) Cp = Cv + R
b) Cv = Cp - R
c) Cp = Cv + PΔV
d) Cv = Cp - PΔV
41. The molar heat capacity of a gas at constant pressure is given by which of the following?
a) CP= (dH/dT)p
b) Cv = (dH/dT)v
c) Cp = (dU/dT)p
d) Cv = (dU/dT)v
42. The enthalpy change in a chemical reaction is given by which of the following?
a) ΔH = ΔU + Δ(PV)
b) ΔH = ΔU - Δ(PV)
c) ΔH = ΔU + PΔV
d) ΔH = ΔU - PΔV
43. The Carnot cycle consists of which of the following processes?
a) Isothermal expansion, adiabatic expansion, isothermal compression, adiabatic compression
b) Isochoric expansion, isobaric expansion, isochoric compression, isobaric compression
c) Adiabatic expansion, isobaric expansion, isothermal compression, adiabatic compression
d) Isothermal expansion, isobaric expansion, isothermal compression, isobaric compression
44. The temperature at which the entropy of a perfect crystalline substance is zero is known as which of the following?
a) Melting point
b) Boiling point
c) Triple point
d) Absolute zero
45. Which of the following laws of thermodynamics is also known as the law of conservation of energy?
a) First law
b) Second law
c) Third law
d) Zeroth law
46. Which of the following is not a thermodynamic potential?
a) Enthalpy
b) Helmholtz free energy
c) Gibbs free energy
d) Work
47. Which of the following statements is true for an adiabatic process?
a) The process is reversible
b) The process is irreversible
c) The process takes place at constant pressure
d) The process takes place at constant temperature
48. The Clausius statement of the second law of thermodynamics is related to which of the following?
a) Entropy
b) Enthalpy
c) Internal energy
d) Heat capacity
49. Which of the following is not a type of thermodynamic equilibrium?
a) Thermal equilibrium
b) Mechanical equilibrium
c) Chemical equilibrium
d) Radiative equilibrium
50. The efficiency of a Carnot engine operating between two heat reservoirs at temperatures T1 and T2 is given by which of the following?
a) η = 1 - T2/T1
b) η = 1 - T1/T2
c) η = T2/T1 - 1
d) η = T1/T2 - 1
I hope you enjoyed this post on 50 basic mcq of thermodynamics. Next time I will come with some more deep MCQ from all the chapters.
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