estimating the potential health hazards due to the use of the cellular phones. The safety guidelines in this field [@Health] are based on the findings from animal experiments that the biological hazards due to radio waves result mainly from the temperature rise in tissues[^1] and a whole-body-averaged specific absorption rate (SAR) below 0.4 W/kg is not hazardous to human health. This corresponds to a limits on the output from the cellular phones (0.6 W at 900 MHz frequency band and 0.27 W at 1.5 GHz frequency band). Obviously, the [*local*]{} absorption rate should be also considered especially in a human head [@WF].

In such studies the following point should be taken into account. The parts of human body (for example, head) posse the eigenfrequencies of electromagnetic oscillations like any compact body. In particular, one can anticipate that the eigenfrequencies of human head are close to those of a dielectric sphere with radius $a\approx 8$ cm and permittivity $\varepsilon
\approx 40$ (for human brain $\varepsilon =44.1$ for 900 MHz and $\varepsilon =42.8$ for 1.5 GHz [@WF]). Certainly, our model is very rough, however for the evaluation of the order of the effect anticipated (see below) it is sufficient. By making use 