Radio Activity

Introduction

Shortly after the discovery of X-rays by Rontgen, Henry Becquerel became more interested in the study of different properties of X-rays. While performing an experiment on X-rays, he observed the photographic plate was affected although it was not exposed to any source of radiation. He later on found tat the traces on the photographic plate wrapped in the paper were due to the radiation emitted by wrapped Uranium salt placed near the photographic plate. He later on concluded that uranium emits a powerful radiation all the time even in the dark and this radiation affects the photographic plate like X-rays. This was an accidental discovery made by Becquerel in 1896.

Experimentally, it was found that the radiation could penetrate paper wrapped and thin silver foils. This radiation from uranium was first named 'Becquerel rays' after the name of Henry Becquerel. Later in 1898 Maurie Curie discovered two more elements, polonium and radium which emits radiation like uranium. The name Becquerel rays was then changed to radioactive rays and the phenomenon was called radioactivity.

Types

(i) Natural Radioactivity: The radioactivity exhibited by element found in nature is called natural activity. The heavier elements found in the periodic table always show this type of radioactivity.

(ii) Artificial Radioactivity: The radioactivity included in an element by means of external agency is called artificial activity. The modern techique of artificial transmutation of elements have made it possible to produce artificial radioactivity in many other elements which is not heavier as in the natural radioactivity.

Natural Radioactivity	Artificial Radioactivity