1. The first law of thermodynamics is a statement of: A) Conservation of mass B) Conservation of momentum C) Conservation of energy D) Conservation of charge Answer: C 2. The internal energy of an ideal gas depends on: A) Volume only B) Pressure only C) Temperature only D) Both volume and temperature Answer: C 3. The process in which no heat is exchanged with the surroundings is called: A) Isothermal B) Adiabatic C) Isochoric D) Isobaric Answer: B 4. For an ideal gas, the specific heat at constant pressure (Cp) is related to the specific heat at constant volume (Cv) by: A) Cp=CvC_p = C_vCp​=Cv​ B) Cp<CvC_p < C_vCp​<Cv​ C) Cp=Cv+RC_p = C_v + RCp​=Cv​+R D) Cp=Cv−RC_p = C_v – RCp​=Cv​−R Answer: C 5. The efficiency of a Carnot engine depends on: A) The nature of the working substance B) The temperatures of the hot and cold reservoirs C) The amount of work done D) The specific heat of the substance Answer: B 6. In a reversible adiabatic process, the work done by an ideal gas is equal to: A) The change in internal energy B) The change in enthalpy C) The heat added to the system D) Zero Answer: A 7. The second law of thermodynamics states that: A) Energy cannot be created or destroyed B) Entropy of the universe always increases C) The total energy of an isolated system is constant D) Heat flows from a colder body to a hotter body Answer: B 8. An isothermal process is one in which: A) Pressure remains constant B) Volume remains constant C) Temperature remains constant D) Entropy remains constant Answer: C 9. The entropy change for a reversible process is: A) Always positive B) Always negative C) Zero D) Infinite Answer: C 10. The Helmholtz free energy is defined as: A) $U-TS$ B) $H-TS$ C) $U+TS$ D) $H+TS$ Answer: A 11. The heat added to a system at constant pressure does what to the enthalpy of the system? A) Increases B) Decreases C) Remains constant D) First increases, then decreases Answer: A 12. A process where volume remains constant is called: A) Isobaric B) Isothermal C) Isochoric D) Adiabatic Answer: C 13. In an adiabatic process, the temperature of an ideal gas: A) Increases if the gas expands B) Decreases if the gas is compressed C) Remains constant D) Changes depending on the sign of work done Answer: D 14. In a polytropic process, the equation PVn=constantPV^n = \text{constant}PVn=constant. For $n=1$, the process is: A) Adiabatic B) Isochoric C) Isothermal D) Isobaric Answer: C 15. The work done in an isobaric process is given by: A) $\Delta U$ B) $P\Delta V$ C) $V\Delta P$ D) $P\Delta T$ Answer: B 16. The efficiency of a Carnot engine is given by: A) TCTH\frac{T_C}{T_H}TH​TC​​ B) 1−TCTH1 – \frac{T_C}{T_H}1−TH​TC​​ C) TH−TCTH\frac{T_H – T_C}{T_H}TH​TH​−TC​​ D) 1+TCTH1 + \frac{T_C}{T_H}1+TH​TC​​ Answer: B 17. In a refrigerator, the coefficient of performance (COP) is defined as: A) The ratio of work input to heat removed from the cold space B) The ratio of heat removed from the cold space to work input C) The ratio of heat input to work output D) The ratio of work output to heat input Answer: B 18. The Rankine cycle is commonly used in: A) Refrigeration B) Air conditioning C) Steam power plants D) Internal combustion engines Answer: C 19. In an Otto cycle, the efficiency depends on the: A) Compression ratio B) Expansion ratio C) Both compression and expansion ratios D) Temperature difference between the heat source and sink Answer: A 20. The process of heat addition in a Diesel cycle is at: A) Constant pressure B) Constant volume C) Constant temperature D) Varying pressure and volume Answer: A 21. The zeroth law of thermodynamics is related to: A) Conservation of energy B) Conservation of entropy C) Thermal equilibrium D) Heat transfer Answer: C 22. The third law of thermodynamics states that the entropy of a perfect crystal at absolute zero temperature is: A) Zero B) Infinite C) Unity D) Negative Answer: A 23. The Gibbs free energy is defined as: A) $H-TS$ B) $U-TS$ C) $U+PV$ D) $H+TS$ Answer: A 24. For a spontaneous process at constant temperature and pressure, the change in Gibbs free energy is: A) Positive B) Negative C) Zero D) Unpredictable Answer: B 25. The chemical potential is defined as the partial derivative of the Gibbs free energy with respect to: A) Temperature B) Pressure C) Volume D) Number of particles Answer: D 26. Entropy is a measure of: A) Energy B) Disorder C) Work D) Heat Answer: B 27. The entropy of a system increases when: A) Heat is removed from the system B) The system is compressed C) The system absorbs heat D) The system is at absolute zero temperature Answer: C 28. The Gibbs free energy change ($\Delta G$) for a process is negative. This implies that the process is: A) Non-spontaneous B) Spontaneous C) At equilibrium D) Impossible Answer: B 29. At equilibrium, the Gibbs free energy of a system is: A) Maximum B) Minimum C) Zero D) Infinite Answer: B 30. The change in enthalpy ($\Delta H$) and the change in entropy ($\Delta S$) are related to the change in Gibbs free energy ($\Delta G$) by: A) $\Delta G=\Delta H+T\Delta S$ B) $\Delta G=\Delta H-T\Delta S$ C) $\Delta G=\Delta H\times T\Delta S$ D) $\Delta G=\Delta H/T\Delta S$ Answer: B 31. The partition function ($Z$) is a measure of: A) The total energy of a system B) The number of microstates accessible to a system C) The entropy of a system D) The heat capacity of a system Answer: B 32. The Boltzmann constant (k) relates: A) Energy to temperature B) Pressure to volume C) Entropy to temperature D) Volume to temperature Answer: A 33. The average energy of a system in thermal equilibrium is given by: A) $kT$ B) $kT/2$ C) $3kT/2$ D) $2kT$ Answer: C 34. In the canonical ensemble, the probability of a system being in a particular state is proportional to: A) The energy of the state B) The exponential of the negative energy of the state divided by $kT$ C) The temperature of the system D) The entropy of the system Answer: B 35. The equipartition theorem states that each degree of freedom contributes an energy of: A) $kT$ B) $kT/2$ C) $2kT$ D) $3kT/2$ Answer: B 36. Fermi-Dirac statistics apply to particles that are: A) Bosons B) Fermions C) Photons D) Phonons Answer: B 37. Bose-Einstein statistics apply to particles that are: A) Fermions B) Bosons C) Neutrons D) Electrons Answer: B 38. The Fermi energy is: A) The average energy of fermions at absolute zero B) The highest occupied energy level of fermions at absolute zero C) The lowest energy level of fermions D) The energy required to ionize a fermion Answer: B 39. Bose-Einstein condensation occurs at: A) High temperatures B) Low temperatures C) Room temperature D) High pressures Answer: B 40. In the context of thermodynamics, an “ideal” gas is one that: A) Does not follow the ideal gas law B) Has zero intermolecular forces C) Has non-zero volume D) Interacts strongly with other gas molecules Answer: B

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