Advantages of using a magnet:

The chemical shift is defined as, δ = (v _Test- v _TMS)/v_op ×10⁶   and is characteristic of the nature of the proton. If we use a magnet of high field strength (which would mean a higher operating frequency), the shift in the signal of the test proton from that of the reference proton would be larger. This helps in the resolution of the signals.

The Bohr magneton is defined as µ _N =e h/2 m_p where e is the electron charge, h is the action constant = h/2π; h being Planck's constant and mp is the mass of the proton.

Substituting the values we get,

µ N = e h/4π m_p

µ _N = 1.602×10 ^-19 C × 6.626×10^-34  Js/4 × 3.141× 1.673×10^{- 27} kg

µ _N = 5.05 × 10^-27 J C s kg^-1 = 5.05 × 10^-27 J T ^-1