At a distance of \(50 \mathrm{~mm}\) (about the distance from your ear to the center of your brain), the \(824.6-\mathrm{MHz}\) microwave radiation from a cell phone has an intensity of \(35 \mathrm{~W} / \mathrm{m}^{2}\). The maximum permissible radiation leaking from a microwave oven at the same distance is \(10 \mathrm{~W} / \mathrm{m}^{2}\). It occurs to you that you could estimate the average magnetic fields generated by the two devices. You also know that people concerned about the possible effects of cell phone radiation on the brain often use a Bluetooth headset, which has an intensity of \(0.080 \mathrm{~W} / \mathrm{m}^{2}\) at a distance of \(50 \mathrm{~mm}\). But in this case the cell phone itself is probably near your waist-on a belt or in a pocket or purse. There must be an improvement in intensities and field magnitudes at the center of the brain or people would not do this. While contemplating these things, you realize that there may also be a concern that the wavelength of cell phone radiation is comparable to the size of the skull.