What is Radioactivity in Physics

The phenomenon of emission of radiation from Uranium and other substances is known A as radioactivity. The substances that emit radiation are known as radioactive elements.

Experiment:

A small quantity of a radioactive element such as radium is placed in a cavity of a lead block in such a way that the radiation from radium can only come out through this cavity. A photographic plate is placed at some distance above the lead black so that the radiation from radium falls upon it. The apparatus is placed in a vacuum light chamber which is evacuated by a powerful pump. This chamber is then placed between the poles of a powerful magnetic field. Under the action of magnetic field, two or three types of radiation are deflected forming three separate images on the photographic plate.

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