a) mu = g*mu_N*I/hbar so g = hbar*mu/(mu_N*I):
ground state: g = -1.188 hbar/mu_N
245 keV: g = -0.3064 hbar/mu_N
b) mu = g*mu_B*S/hbar and mu = mu_B so g = hbar/S = 2*hbar
c) mu = g*mu_N*I/hbar = -1.913 mu_N/hbar