ABSTRACT
Radioactivity was discovered by accident in 1896 by Becquerel, who found that the rays emitted by a sample of uranium were similar to x-rays
(discovered a few months before by Roentgen) but appeared spontaneously from the uranium sample. These new rays had a very high penetrating power and could also cause ionisation of the air just like x-rays. Soon after, many other naturally occurring radioactive elements were discovered, chief among these being radium and polonium by Marie Curie in 1911.
