It is important to note that Albert Einstein did not discover radioactivity. Radioactivity was first discovered by Henri Becquerel in 1896. Becquerel observed that uranium salts emitted rays that could expose photographic plates even in the absence of external sources of light. This discovery paved the way for further research on radioactivity.
However, Einstein made significant contributions to the understanding of the nature of radiation and the theoretical framework behind it. In 1905, Einstein published his groundbreaking paper on the photoelectric effect, which explained the behavior of light interacting with matter. This paper contributed to the development of quantum theory and provided a new perspective on the particle-like nature of light.
Einstein's work on the photoelectric effect, for which he was awarded the Nobel Prize in Physics in 1921, played a crucial role in the understanding of radiation and its interaction with atoms. His explanation of the photoelectric effect introduced the concept of photons as discrete packets of energy, which helped scientists comprehend the nature of electromagnetic radiation, including radioactivity.
Therefore, while Einstein did not discover radioactivity itself, his work on the photoelectric effect and his broader contributions to physics greatly influenced the understanding and interpretation of radiation phenomena.