1.7.6
The magnetic field is well defined for points far from a magnetic dipole moment (far field, R > a; see Fig. 1.35).This means that the distance R must be large compared to the size of the magnetic dipole radius a or length l, or the size of the magnetic dipole a or l must be small compared to the distance R:
FIGURE 1.35 Geometric configuration for a magnetic dipole moment.
