Which one of the following pairs of rays is not electromagnetic in nature ?

Radiation is categorized into electromagnetic waves and particulate radiation. Gamma rays and X-rays are types of electromagnetic waves. In contrast, alpha and beta rays are particulate in nature. Alpha rays consist of high-speed helium nuclei (two protons and two neutrons) [1]. Beta rays are composed of swiftly moving electrons or positrons ejected from a nucleus. Similarly, cathode rays are beams of negatively charged electrons produced in manufactured devices like X-ray tubes [1]. Since alpha rays and beta rays are both composed of physical particles (helium nuclei and electrons/positrons respectively) rather than photons, they are not electromagnetic in nature [1]. Therefore, the pair consisting of alpha rays and beta rays is the correct choice as neither component is electromagnetic.

Sources

1. [1] https://www.sciencedirect.com/topics/engineering/ionizing-radiation