Complete the following statement: The term ionizing radiation does not apply to
(a) alpha particles. (c) X-ray photons. (e) radio photons.
(b) electrons. (d) positrons.
The ionizing radiation is anyradiation that is capable to ionize a substance, i.e. liberate an electron from an atom or a molecule inside. It requires the ionizing particle to have sufficient energy, e.g. moving at a relativistic speed. Ionizing radiation includes, in particular, cosmic rays, alpha, beta (to which electrons and positrons belong) and gamma rays, X-rays, etc. Thus, only radio photons are not included, which is explainable, as these are long-wavelength, i.e. low-energy quants.