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the start
eia.gov
Wilhelm Roentgen, a German physicist, discovered X-rays -
discovery
eia.gov
J. J. Thomson (England) discovered the electron -
finding radioactive elements
eia.gov discovered the radioactive elements radium and polonium by mary curie -
new rays
eia.gov Ernest Rutherford (Canada) discovered two kinds of rays emitting from radium. He called the first rays, alpha rays; and the more penetrating rays, beta rays. -
more on elements
eia.govFrederick Soddy (England) observed spontaneous disintegration of radioactive elements into variants. He called these isotopes. -
radioactive decay
eia.govRutherford and Soddy published the theory of radioactive decay -
e=mc2
eia.govAlbert Einstein (U.S. immigrant from Germany) wrote the special theory of relativity. He created a new era of physics when he unified mass, energy, magnetism, electricity, and light. One of the most significant events of the 20th century was Einstein's developing the formula of E=mc2 -
nucleus
Rutherford (United Kingdom) discovered the nucleus of the atom