For B=2T photon energy transmitted from mJ=-3/2 to mJ=-1/2 levels and from mJ=-1/2 to mJ=1/2 levels is 1meV.
When we apply magnetic field of 10T and we will take into account the hyperfine splitting then the photon energy transmitted from mJ=-3/2 to mJ=-1/2 levels and from mJ=-1/2 to mJ=1/2 levels will be different and for first 4.999998424 meV and for second 5.000004728 meV. But I am not sure.