Cell phone antennas (which are built inside the phone) are a few centimeters in size because this is how big the waves making up the cell phone signal are. Intensity or brightness is related to amplit...Cell phone antennas (which are built inside the phone) are a few centimeters in size because this is how big the waves making up the cell phone signal are. Intensity or brightness is related to amplitude of the wave and the number of photons, not the energy of an individual photon. Electromagnetic waves with frequencies higher than the visible part of the spectrum are said to be ionizing because they have enough energy to ionize (remove an electron) from a molecule.
