Counting microstates (a) Consider N = 4 noninteracting spins with magnetic moment that can point either parallel or antiparallel to the magnetic field B.

• Counting microstates (a) Consider N = 4 noninteracting spins with magnetic moment µ that can point either parallel or antiparallel to the magnetic field B. If the total energy E = −2µB, what are the accessible microstates and the probability that a particular spin is up or down? (b) Consider N = 9 noninteracting spins with total energy E = −µB. What is the number of up spins, the number of accessible microstates, and the probability that a particular spin is up or down?