Final answer:
The statement that exposure is applicable only for photons is false. Exposure to ionizing radiation includes not only photons, such as X-rays and gamma rays, but also other particles like alpha and beta particles that can ionize matter.
Step-by-step explanation:
The statement "Exposure as a physical quantity is applicable for photons only?" is false. Exposure can refer to the amount of ionizing radiation, such as photons, but the term can also apply to other particles that cause ionization, such as alpha and beta particles. Photons, which include X-rays and gamma rays, are a form of electromagnetic radiation that can lead to exposure when they interact with matter and produce ionizations. However, other particles, not just photons, can also cause ionizing radiation exposure.
For example, alpha particles, which are helium nuclei, and beta particles, which are electrons or positrons, can also cause exposure by ionizing atoms within living tissue. Therefore, the concept of exposure is not limited to only photons, but also includes other ionizing radiation forms.