GRE Subject 2026 Practice Test Physics Statistical Physics Free Quiz 2

11. What is the Stefan-Boltzmann law?

A. P = σAT⁴ B. P = σAT⁴ C. P = σAT⁴ D. P = σAT⁴

12. What does the equipartition theorem state?

A. k_B T B. ½k_B T C. ½k_B T D. 2k_B T

13. What is the heat capacity at constant pressure?

A. (∂U/∂T)_V B. (∂U/∂T)_P C. (∂H/∂T)_P D. (∂H/∂T)_V

14. What is the Gibbs free energy?

A. G = U + PV - TS B. G = U - TS C. G = H + TS D. G = H - TS

15. What is the Helmholtz free energy?

A. F = H - TS B. F = U - TS C. F = U + PV D. F = G + PV

16. What ensemble has fixed temperature, volume, and chemical potential?

A. Grand canonical B. Canonical C. Microcanonical D. Isothermal-isobaric

17. What is the sum over all states of e^{-E/k_B T}?

A. Entropy B. Partition function C. Free energy D. Internal energy

18. How is the free energy related to the partition function?

A. F = -k_B T ln Z B. F = k_B T ln Z C. F = -k_B T Z D. F = k_B T Z

19. What is the average energy in terms of the partition function?

A. E = ∂ ln Z/∂β B. E = -∂ Z/∂β C. E = -∂ ln Z/∂β D. E = ∂ Z/∂β

20. What occurs when bosons occupy the same ground state at low temperatures?

A. Fermi sea B. Ideal gas C. van der Waals gas D. Bose-Einstein condensation