A positive electric current moving in a circular loop creates a magnetic dipole moment (μ) 

   that depends on the current (I), and the Area (A) that the loop encloses is,

                                        𝝻 = IA        

If we treat the proton as the spherical particle that is rotating about an axis, we can imagine that it consists of infinitely many such positive current loops that can add up to form its own magnetic dipole moment, μ.

Both proton and neutron have magnetic moments, which means that although neutrons have a net charge of zero, they must be composed of even smaller bits that do have a charge that is quarks.

In the same way that we expressed the magnetic dipole moment of the electron using "The Bohr magneton", we typically express the magnetic moment of protons and neutrons using the Bohr Magneton.

Recall that for electrons, we combined the electron spin and the orbital angular momentum and called this combination the total angular momentum. However, nuclei of atoms have only one angular momentum and so we call this intrinsic total angular momentum of the nuclear spin ( mI).

 The nuclear spin can be calculated using the nuclear spin quantum number, I .