Radioactivity

The property possessed by some elements, such as uranium, of giving off alpha, beta, or gamma rays.

W.C. Rontgen in 1895 discovered the X-Ray, just after it in 1896 Henery Bequerel find the fact that Uranium and its salts have radiate some invisible rays, which can penetrate the thin foils of metal, ionise the gases and produce fluorescent in Zinc Sulphide. These invisible rays are known as Beguerel-rays or Radioactive rays and the property of materials to emit such rays is RadioActivity.

These rays are of three types.