What is the primary factor in determining how well the body will absorb EMF with frequencies in the resonance range of 30-300 MHz?

• A. The frequency of the emitter
• B. The intensity of the EMF
• C. The exposure duration
• D. The distance from the source

Answer: (A)

In this RF range, how well the body absorbs energy is governed mainly by how the tissue’s dielectric properties respond at the applied frequency. The body acts like a lossy dielectric, and its tissues have frequency-dependent permittivity and conductivity. At certain frequencies within 30–300 MHz, the coupling between the electromagnetic field and the tissues is more efficient, so energy transfer into the body—and the resulting absorption—peaks. That intrinsic ability to absorb per unit of field energy is set by the emitter’s frequency.

The other factors—how strong the field is (intensity), how long the exposure lasts, and how far you are from the source—change the total energy delivered to the body, but they don’t change how effectively energy is absorbed per unit of field energy. So, the frequency of the emitter is the primary determinant of absorption in this resonance range.