Imagine a system in local thermal equilibrium at temperature T which contains both massless spin-1/2 particles (Weyl fermions) and massless spin-1 particles, both with vanishing chemical potential. For which particle species will the contribution to the energy density be larger? (a) Spin-1/2 particles (b) Spin-1 particles (c) They will be equal (d) Not enough information

Please solve it in 30 minute

6. We used each of the following methods, which of these do not use empirical data? (a) Hartree-Fock (HF) (b) B3LYP (c) PM3 (d) both a and b In 1-2 sentences, explain your reas reasoning:

Bohr’s model can be used for hydrogen-like ions—ions thathave only one electron, such as He + and Li2 + . (a) Why isthe Bohr model applicable to He + ions but not to neutral Heatoms? (b) The ground-state energies of H, He + , and Li2 + aretabulated as follows:By examining these numbers, propose a relationship betweenthe ground-state energy of hydrogen-like systems and thenuclear charge, Z. (c) Use the relationship you derive in part(b) to predict the ground-state energy of the C5 + ion.