How do the resonance frequencies of protons and electrons compare in the same magnetic field?

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magnetic resonance Figure 1: Precession of a magnetic dipole moment μ in the presence of a constant field H and a rotating field H′ (see text)

In a given magnetic field, the resonance frequencies of protons and electrons differ significantly due to their distinct physical properties. The resonance frequency, known as the Larmor precession frequency, depends on the particle's magnetic moment and angular momentum.

Because electrons have a much larger magnetic moment relative to their mass than protons, their resonance frequencies are substantially higher. For example, in a magnetic field of 10 kilogauss:

The proton NMR frequency is 42.58 megahertz, placing it in the radio-frequency range.
The ESR frequency of a free electron spin is 28,000 megahertz, placing it in the microwave or radar range.

In summary, for the same external magnetic field, the electron resonance frequency is orders of magnitude higher than that of the proton.1